Sour Cherry Charlottes

Toss together cherries, sugar, and cornstarch in a medium bowl. Set aside; let cherries thaw slightly, about 35 minutes.

Preheat the oven to 350°F. Using a pastry brush, generously brush one side of each slice of bread with the butter. Reserve 6 slices; cut remaining slices in half to form 36 rectangles. Line sides and bottom of each cup of a jumbo (6-cup) muffin tin with 6 rectangles, overlapping bread and placing buttered side against tin.

Toss cherry mixture to combine. Spoon into bread-lined cups. Top each with a reserved bread square, buttered side down; press firmly onto cherries.