Heat a large skillet over medium-heat. Add the bacon or turkey bacon and cook through, about seven minutes. Remove from pan and drain on paper towels.
Pour the excess grease away, but don't wipe pan. Add the onion, season with salt and pepper, and stir occasionally until it starts to soften, about five minutes.
Add the mushrooms and cook until vegetables are soften, about three to five minutes.
Meanwhile, crack the eggs into a bowl and whisk together. Add the milk and whisk well.
Add the bacon back to the pan. Pour the eggs over top of the bacon and vegetable mixture. Move around in the pan frequently. You want the eggs to cook, but not get brown.
Flip the eggs to cook the other side. Add salt and pepper to taste. Add the cheese on top, cover with a lid, and remove from heat.
Let the cheese melt for a few minutes. Divide into servings.