1Peel and slice the onions on a mandoline to about a quarter inch thickness, then toss to break up all the rings.
2Make the spice blend by combining salt, black pepper, smoked paprika, granulated garlic, dry mustard, brown sugar, cayenne, and fresh thyme leaves in a bowl.
3Toss the onions with olive oil, then add half the spice blend and toss again. Repeat with the remaining spice blend and toss.
4Create a layer of onions in a greased 13x9 baking dish.
5Top the onion layer with 2 ounces of mild cheddar and 2 ounces of gruyere.
6Add a second layer of onions.
7Top with another 2 ounces of mild cheddar, 2 ounces of gruyere, and 1/2 cup of freshly grated pecorino romano.
8Dot the top with small pieces of butter.
9Cover tightly with foil and bake at 350 degrees for 45 minutes.
10Remove the foil and bake for another 30 minutes.
Ingredients
4 whole sweet onion
2 tsp kosher salt
1 tsp black pepper
1 tsp smoked paprika
1 tsp granulated garlic
1 tsp dry mustard
2 tsp brown sugar
1/2 tsp cayenne
1 tsp fresh thyme leaves, stripped
2 tbsp olive oil
4 oz Tillamook mild cheddar cheese, freshly grated
4 oz gruyere cheese, freshly grated
1/2 cup pecorino romano cheese, freshly grated
3 tbsp butter
Equipment
mandolinemixing bowlsmall bowlbaking dish
Tips
Use either light or dark brown sugar.
You could use sharp cheddar instead of mild.
You could use parmesan or reggiano or grana padano instead of pecorino romano.