01 -
Mix the gruyère, brie, and cheddar together, seasoning them with paprika, black pepper, and oregano.
02 -
Generously butter one side of both slices of bread. Spread Dijon mustard on the unbuttered sides.
03 -
Place the cheese mixture on the mustard side of one slice of bread, then sandwich it with the remaining slice of bread, mustard side inward.
04 -
Fry the sandwich over low-medium heat in a non-stick pan. Cover the pan with a lid to help the cheese melt quickly. No additional butter or oil is needed as the bread is already buttered.
05 -
Cook until golden brown, approximately 1-3 minutes per side. Flip the sandwich and repeat for the other side.
06 -
Remove the sandwich from the pan and enjoy immediately.