1. Preheat oven to 375 degrees. Lightly butter 6 standard muffin cups. With a rolling pin, flatten bread slices slightly and, with a 4 1/4-inch cookie cutter, cut into 8 rounds. Cut each round in half, then press 2 halves into each muffin cup, overlapping slightly and making sure bread comes up to edge of cup. Use extra bread to patch any gaps. Brush bread with remaining butter.

2. In a large skillet, cook bacon over medium, until almost crisp, 4 minutes, flipping once. (It will continue to cook in the oven.) Lay 1 bacon slice in each bread cup and crack an egg over each. Season with salt and pepper. Bake until egg whites are just set, 20 to 25 minutes. Run a small knife around cups to loosen toasts. Serve immediately.