Bake for 15 minutes. Remove from oven and reshape the bacon around the wells/cups if moved; blot out excess grease, leaving only 10% or so of it behind for flavor.
In a large bowl, mix eggs, sharp cheddar, monterey jack, dijon mustard, minced onion, garlic powder, salt, and pepper until well-combined.
Evenly distribute in the muffin tin and bake for an additional 15-20 minutes (or until a toothpick comes out of the center clean). If you have extra egg mixture, make it into an omelette in your skillet!