3 Tbsp unsalted butter
1 Tbsp olive oil
2 onions, thinly sliced
8 thin slices white bread
10 ounces Muenster Cheese (or taleggio cheese, rind removed, sliced)
8 ounces thinly sliced ham
1 green apple, thinly sliced
Melt 1 tablespoon butter with olive oil in large skillet over medium-low heat. Add the onions and cook, stirring occasionally, until soft and caramelized, about 20 minutes. (For a shortcut, use onion marmalade in place of caramelized onions.)
Lay out 4 slices of bread. Top with half the cheese, then half the ham. Layer the caramelized onions, apple slices and the remaining ham and cheese on top, then the remaining bread slices.
Wipe out skillet (or use electric skillet); melt 1 tablespoon butter over medium-low heat. Add 2 sandwiches and cook, pressing gently with spatula, until the bottom is golden and the cheese begins to melt, about 4 minutes. Flip and cook until golden, about 4 more minutes. Repeat with the remaining butter and sandwiches.
*Recipe adapted from Food Network Magazine