10 very thin slices firm white sandwich bread
2 TBS unsalted butter, melted
1/2 cup sour cream
3 1/2 oz caviar
Preheat the oven to 350 degrees F.
Brush the bread with the melted butter and cut out 40 moons, then arrange them on a large baking sheet and bake (buttered sides up) in the middle of the oven until pale golden (about 10 minutes).
Allow to cool completely.
Serve the toasts topped with sour cream and caviar.
Note: Toasts may be prepared 1 day ahead and kept in an airtight container at room temperature.