01 -
Heat oven to 400°F, line baking sheet with parchment.
02 -
Spread butter generously on one side of each bread slice.
03 -
Sprinkle Parmesan on buttered sides if using, press into butter.
04 -
Place 4 slices butter-side down, add mixed cheeses, top with remaining bread butter-side up.
05 -
Cook on bottom rack 4-5 minutes, flip, cook 2-3 minutes more until golden.
06 -
Let cool briefly before cutting and serving.