1In a small bowl, mix together the flour, baking powder, baking soda, and salt, then whisk to combine and set aside.
2In a small bowl, mix together the flour, baking powder, baking soda, and salt, then whisk to combine and set aside.
3In a small bowl, mix together the flour, baking powder, baking soda, and salt, then whisk to combine and set aside.
4Chop the Oreo cookies into small pieces and set aside.
5Chop the Oreo cookies into small pieces and set aside.
6Chop the Oreo cookies into small pieces and set aside.
7In a large bowl, beat the butter for 30 seconds.
8In a large bowl, beat the butter for 30 seconds.
9In a large bowl, beat the butter for 30 seconds.
10Add the sugar and the oil to the bowl and beat for 2 minutes until the mixture is creamy and fluffy.
11Add the sugar and the oil to the bowl and beat for 2 minutes until the mixture is creamy and fluffy.
12Add the sugar and the oil to the bowl and beat for 2 minutes until the mixture is creamy and fluffy.
13Add the sour cream and the vanilla to the bowl and mix to combine.
14Add the sour cream and the vanilla to the bowl and mix to combine.
15Add the sour cream and the vanilla to the bowl and mix to combine.
16Add 1/3 of the milk to the bowl and mix on low to combine.
17Add 1/3 of the milk to the bowl and mix on low to combine.
18Add 1/3 of the milk to the bowl and mix on low to combine.
19Then add 1/3 of the dry ingredient mixture to the bowl and mix to combine on low.
20Then add 1/3 of the dry ingredient mixture to the bowl and mix to combine on low.
21Then add 1/3 of the dry ingredient mixture to the bowl and mix to combine on low.
22Add the remaining milk and stir to combine, and finish with the rest of the flour and stir on low.
23Add the remaining milk and stir to combine, and finish with the rest of the flour and stir on low.
24Add the remaining milk and stir to combine, and finish with the rest of the flour and stir on low.
25With clean beaters, whip the egg whites for about 5 minutes until they have stiff peaks.
26With clean beaters, whip the egg whites for about 5 minutes until they have stiff peaks.
27With clean beaters, whip the egg whites for about 5 minutes until they have stiff peaks.
28Add half of the whipped egg whites to the cake batter bowl and fold with a spatula carefully until combined.
29Add half of the whipped egg whites to the cake batter bowl and fold with a spatula carefully until combined.
30Add half of the whipped egg whites to the cake batter bowl and fold with a spatula carefully until combined.
31Add the remaining egg white mixture and the chopped Oreos along with it, and fold gently with a spatula until the batter is incorporated.
32Add the remaining egg white mixture and the chopped Oreos along with it, and fold gently with a spatula until the batter is incorporated.
33Add the remaining egg white mixture and the chopped Oreos along with it, and fold gently with a spatula until the batter is incorporated.
34Divide the batter evenly between 3 greased 8-inch cake pans lined with parchment paper.
35Divide the batter evenly between 3 greased 8-inch cake pans lined with parchment paper.
36Divide the batter evenly between 3 greased 8-inch cake pans lined with parchment paper.
37Bake the cake layers in a preheated oven for 35 minutes or until a toothpick comes off clean when inserted.
38Bake the cake layers in a preheated oven for 35 minutes or until a toothpick comes off clean when inserted.
39Bake the cake layers in a preheated oven for 35 minutes or until a toothpick comes off clean when inserted.
40Remove the cakes from the oven and let them cool down completely before frosting.
41Remove the cakes from the oven and let them cool down completely before frosting.
42Remove the cakes from the oven and let them cool down completely before frosting.
43For the cookies and cream mousse filling, place the chopped white chocolate in a bowl along with 1/4 cup of heavy cream.
44For the cookies and cream mousse filling, place the chopped white chocolate in a bowl along with 1/4 cup of heavy cream.
45For the cookies and cream mousse filling, place the chopped white chocolate in a bowl along with 1/4 cup of heavy cream.
46Microwave the white chocolate and heavy cream mixture until the chocolate has melted, then let it cool down completely.
47Microwave the white chocolate and heavy cream mixture until the chocolate has melted, then let it cool down completely.
48Microwave the white chocolate and heavy cream mixture until the chocolate has melted, then let it cool down completely.
49Beat the cream cheese with a mixer for 45 seconds.
50Beat the cream cheese with a mixer for 45 seconds.
51Beat the cream cheese with a mixer for 45 seconds.
52Add the cooled white chocolate and heavy cream mixture to the bowl and beat for 30 seconds to combine.
53Add the cooled white chocolate and heavy cream mixture to the bowl and beat for 30 seconds to combine.
54Add the cooled white chocolate and heavy cream mixture to the bowl and beat for 30 seconds to combine.
55In a separate bowl, beat the remaining 3/4 cup of heavy cream for 2 to 3 minutes until stiff peaks form.
56In a separate bowl, beat the remaining 3/4 cup of heavy cream for 2 to 3 minutes until stiff peaks form.
57In a separate bowl, beat the remaining 3/4 cup of heavy cream for 2 to 3 minutes until stiff peaks form.
58Add the whipped cream and vanilla to the bowl with the cream cheese and white chocolate mixture and fold to combine.
59Add the whipped cream and vanilla to the bowl with the cream cheese and white chocolate mixture and fold to combine.
60Add the whipped cream and vanilla to the bowl with the cream cheese and white chocolate mixture and fold to combine.
61Add the chopped Oreos to the mousse mixture and mix.
62Add the chopped Oreos to the mousse mixture and mix.
63Add the chopped Oreos to the mousse mixture and mix.
64For the cookies and cream frosting, beat the butter with a mixer for 30 seconds.
65For the cookies and cream frosting, beat the butter with a mixer for 30 seconds.
66For the cookies and cream frosting, beat the butter with a mixer for 30 seconds.
67Add the cream cheese and beat with the butter for 1 more minute.
68Add the cream cheese and beat with the butter for 1 more minute.
69Add the cream cheese and beat with the butter for 1 more minute.
70Add the powdered sugar and the salt and mix on low until incorporated.
71Add the powdered sugar and the salt and mix on low until incorporated.
72Add the powdered sugar and the salt and mix on low until incorporated.
73Raise the speed to medium high and beat for 2 minutes until the mixture is creamy.
74Raise the speed to medium high and beat for 2 minutes until the mixture is creamy.
75Raise the speed to medium high and beat for 2 minutes until the mixture is creamy.
76Add the vanilla and 1/2 cup of finely powdered Oreo crumbs and mix until incorporated.
77Add the vanilla and 1/2 cup of finely powdered Oreo crumbs and mix until incorporated.
78Add the vanilla and 1/2 cup of finely powdered Oreo crumbs and mix until incorporated.
79To assemble the cake, place one cake layer on top of a serving plate and brush with some sugar syrup if desired.
80To assemble the cake, place one cake layer on top of a serving plate and brush with some sugar syrup if desired.
81To assemble the cake, place one cake layer on top of a serving plate and brush with some sugar syrup if desired.
82Pipe a ring of cookies and cream frosting around the edges of the cake layer.
83Pipe a ring of cookies and cream frosting around the edges of the cake layer.
84Pipe a ring of cookies and cream frosting around the edges of the cake layer.
85Spoon some of the cookies and cream mousse in the center and use a spatula to spread it out evenly.
86Spoon some of the cookies and cream mousse in the center and use a spatula to spread it out evenly.
87Spoon some of the cookies and cream mousse in the center and use a spatula to spread it out evenly.
88Top with another cake layer, brush with sugar syrup again if desired.
89Top with another cake layer, brush with sugar syrup again if desired.
90Top with another cake layer, brush with sugar syrup again if desired.
91Pipe a ring of cookies and cream frosting around the edges of the second layer.
92Pipe a ring of cookies and cream frosting around the edges of the second layer.
93Pipe a ring of cookies and cream frosting around the edges of the second layer.
94Spoon more of the cookies and cream mousse in the center and spread with a spatula.
95Spoon more of the cookies and cream mousse in the center and spread with a spatula.
96Spoon more of the cookies and cream mousse in the center and spread with a spatula.
97Top with the remaining cake layer.
98Top with the remaining cake layer.
99Top with the remaining cake layer.
100Spread the cookies and cream frosting on top of the cake and on the sides.
101Spread the cookies and cream frosting on top of the cake and on the sides.
102Spread the cookies and cream frosting on top of the cake and on the sides.
103Use a bench scraper or cake scraper to smooth out the sides and an offset spatula to smooth out the top.
104Use a bench scraper or cake scraper to smooth out the sides and an offset spatula to smooth out the top.
105Use a bench scraper or cake scraper to smooth out the sides and an offset spatula to smooth out the top.
106Use your hands to attach the remaining 1/2 cup of Oreo crumbs to the side of the cake on the bottom.
107Use your hands to attach the remaining 1/2 cup of Oreo crumbs to the side of the cake on the bottom.
108Use your hands to attach the remaining 1/2 cup of Oreo crumbs to the side of the cake on the bottom.
109Place the cake in the fridge for 30 minutes while making the ganache drip.
110Place the cake in the fridge for 30 minutes while making the ganache drip.
111Place the cake in the fridge for 30 minutes while making the ganache drip.
112Heat up the heavy cream until hot and pour over the chopped chocolate in a bowl.
113Heat up the heavy cream until hot and pour over the chopped chocolate in a bowl.
114Heat up the heavy cream until hot and pour over the chopped chocolate in a bowl.
115Whisk until the chocolate has melted entirely, then let the ganache cool down for about 10 to 15 minutes.
116Whisk until the chocolate has melted entirely, then let the ganache cool down for about 10 to 15 minutes.
117Whisk until the chocolate has melted entirely, then let the ganache cool down for about 10 to 15 minutes.
118Pour the ganache on top of the cake using a spoon or a piping bag.
119Pour the ganache on top of the cake using a spoon or a piping bag.
120Pour the ganache on top of the cake using a spoon or a piping bag.
121To create drips, place the ganache in a piping bag, snip a small hole with scissors, and place the piping bag on the edge of the cake while spinning the cake plate around.
122To create drips, place the ganache in a piping bag, snip a small hole with scissors, and place the piping bag on the edge of the cake while spinning the cake plate around.
123To create drips, place the ganache in a piping bag, snip a small hole with scissors, and place the piping bag on the edge of the cake while spinning the cake plate around.
124Pour ganache on top of the cake and use a spatula to smooth it out.
125Pour ganache on top of the cake and use a spatula to smooth it out.
126Pour ganache on top of the cake and use a spatula to smooth it out.
127Place the cake in the fridge for 20 minutes so the ganache has a chance to set.
128Place the cake in the fridge for 20 minutes so the ganache has a chance to set.
129Place the cake in the fridge for 20 minutes so the ganache has a chance to set.
130Pipe the remaining frosting on top of the cake using a tip 4B.
131Pipe the remaining frosting on top of the cake using a tip 4B.
132Pipe the remaining frosting on top of the cake using a tip 4B.
133Decorate the cake with halved Oreo cookies and more cookie crumbs if desired.
134Decorate the cake with halved Oreo cookies and more cookie crumbs if desired.
135Decorate the cake with halved Oreo cookies and more cookie crumbs if desired.