Preheat your campfire grill or set up a campfire with a grate over the flames.
In a large bowl, whisk together the eggs and milk until well combined.
Stir in the cooked breakfast sausage or bacon, shredded cheese, diced bell peppers, and diced onions.
Season the mixture with salt and pepper to taste.
Grease a muffin tin with cooking spray or butter.
Pour the egg mixture evenly into the muffin cups, filling each cup about three-quarters full.
Place the muffin tin on the grill or over the campfire, ensuring it is positioned on a stable surface.
Cook the frittatas for 15-20 minutes, or until they are set and golden brown on top.
Carefully remove the muffin tin from the heat using heat-resistant gloves or oven mitts.
Allow the frittatas to cool for a few minutes before removing them from the muffin tin.
Serve the Campfire Breakfast Muffin Tin Frittatas warm and enjoy the deliciousness!
