Directions:

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 cut, overlapping slightly and making sure bread comes up to edge of cup. Use extra bread to patch any gaps [and bottom of muffin cup]. 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.

See video at:
http://www.marthastewart.com/330179/bacon-egg-and-toast-cups