Caramelized Onion and Sour Cherry Tartine

Preheat oven to 475°F. Heat oil in a medium skillet over medium-low. Add onion, brown sugar, and salt; cook, stirring occasionally, until onions are soft and golden brown, 18 to 20 minutes.

Spread butter evenly on 1 side of each slice of bread. Place on a baking sheet, butter side up, and bake until lightly browned, about 5 minutes. Top bread evenly with cherries, caramelized onions, and cheese. Bake at 475°F until cheese is melted and lightly browned, 8 to 10 minutes. Sprinkle evenly with thyme.