01 - Melt butter with chopped sage in a small saucepan over medium-low heat until aromatic, about 2 minutes. Remove from heat and set aside.
02 - Arrange sliced sharp cheddar and thin apple slices between two slices of sourdough bread for each sandwich.
03 - Brush the exterior of each assembled sandwich generously with the sage-infused butter.
04 - Place sandwiches in a skillet and cook over medium heat for 3 to 4 minutes per side, until golden brown and the cheese has fully melted.
05 - Slice each sandwich in half and serve while hot.