01 -
In a large bowl, thoroughly combine ground beef with salt, black pepper, paprika, garlic powder, and onion powder using hands or a fork for even distribution.
02 -
Heat 1 tablespoon of butter in a non-stick frying pan over medium heat. Add chopped onion and sauté for 5-7 minutes, stirring regularly until softened and golden brown. Set aside to cool slightly.
03 -
Divide seasoned beef into two portions and form into cutlets slightly larger than the bread slices, ensuring even thickness for consistent cooking.
04 -
Return pan to medium heat with remaining tablespoon of butter. Add both cutlets and fry for 4-5 minutes per side until cooked through. In the final minute, top each with 2 slices of cheddar and 1 slice of mozzarella cheese, allowing cheese to melt thoroughly.
05 -
Spread mayonnaise over one slice of bread. Place a cheesy beef cutlet onto a bread slice, top generously with caramelized onions, and cap with a second slice of bread. Repeat for second sandwich.
06 -
Place assembled sandwiches back into the pan over medium heat. Toast for 3-4 minutes per side, pressing gently with a spatula as you cook, until the bread is deeply golden and crisp and the cheese has fully melted.
07 -
Remove from pan, let rest briefly, then cut in half and serve hot. Complement with pickled cucumbers, coleslaw, or French fries as desired.