01 - Heat a large skillet or griddle over medium setting.
02 - Spread a thin layer of softened butter on one side of each slice of sourdough bread.
03 - On the unbuttered sides of two bread slices, evenly distribute 1 tablespoon apple butter each.
04 - Lay slices of Brie cheese evenly over apple butter. Add thin apple slices and thyme leaves if desired.
05 - Place the remaining bread slices on top, buttered sides facing outward.
06 - Transfer sandwiches to the skillet. Cook for 3 to 4 minutes per side, pressing gently with a spatula, until bread is golden and cheese melts.
07 - Remove grilled sandwiches from heat, slice each in half, and serve immediately.