Spray or grease a 6-count muffin pan REALLY WELL, to ensure cups don't stick.
Partially cook the bacon to render the fat. It should still be pliable and not crispy. When done cooking, drain with paper towels and allow to cool slightly.
If you haven't sautéed the mushrooms, do so now.
Set the mushrooms and bacon aside.
Preheat oven to 400 degrees.
Using a cookie cutter or the top of a glass, cut the bread into circles roughly the size of the base of the muffin cup.
Place one bread circle into each muffin cup.
Wrap 2 slices of bacon loosely around the sides of each cup {on top of the bread}, overlapping if necessary. This will form the edges of the cup itself, and the bacon will adhere to the bread when cooking.
Place about 1 tbs of the mushrooms and tomato into the cup, on top of the bread circle.
Break one whole egg into the cup.
Sprinkle the top of each egg with salt, pepper, and a pinch of parsley.
Bake for 15-20 minutes, or until bacon is cooked to crisp and the egg is of desired consistency.