1Prepare the onion roll: Thinly slice onions into rings. Sprinkle grated cheese on a baking tray lined with parchment paper. Spread onions on top, brush with oil, and season with salt and paprika. Bake at 200°C (top/bottom heat) for approx. 30 min until golden brown. Let cool.
2Filling: Fry the ground beef in oil until crumbly. Season with salt and paprika.
3Sauce: Mix mayonnaise, ketchup, mustard, pickle juice, sweet paprika, salt and pepper.
4Assemble the roll: Flip the onion sheet over (onions facing down). Place cheddar in the center, spread ground beef over it. Bake again for 5–10 minutes.
5Top with lettuce, pickles, and sauce. Roll up and slice.