> 6 oz sharp Cheddar cheese, divided
> 4 tbsp butter, softened
> 8 slices sourdough bread
> 8 tsp grainy Dijon mustard, divided
> 1 small Gala or Fuji apple, cored and very thinly sliced
Preheat oven to 425°F, placing top rack in upper third of oven. Coarsely grate the Cheddar.
Line a sheet pan with parchment. Spread the butter on 1 side of each bread slice. Arrange 4 slices of bread butter-sides down on prepared sheet pan. Spread bread with the mustard, then top with apple slices, Cheddar, and remaining 4 slices of bread, butter-sides up. Press down gently.
Bake the sandwiches 10–12 min., until cheese is melted and bread is golden brown, turning over once halfway through.