Corned-Beef Egg Cups

Preheat oven to 375°F. Brush 6 muffin cups (the deeper the better) with melted butter. With a rolling pin, slightly flatten slices of potato bread (trimming off the crusts if desired). Press into prepared cups and brush with more butter.

Melt 1 tablespoon butter in a small skillet over medium heat. Add shallot and cook, stirring, until softened, 2 to 3 minutes. Remove from heat and stir in corned beef and baby spinach.

Divide filling evenly among cups. Crack 1 large egg into each and season with salt and pepper. Bake until egg whites are almost set, 15 to 20 minutes. Let stand 5 minutes before serving.