Preheat your campfire grill or set up a campfire with a grate over the flames.
In a large bowl, whisk together the eggs until well beaten.
Stir in the cooked breakfast sausage or bacon, diced bell peppers, onions, and shredded cheese.
Season the mixture with salt and pepper to taste.
Grease a cast-iron skillet with cooking spray or butter.
Pour the egg mixture into the skillet, spreading it out evenly.
Place the skillet on the grill or over the campfire, ensuring it is positioned on a stable surface.
Cook the frittata for 15-20 minutes, or until it is set in the center and golden brown on top.
Remove the skillet from the heat using heat-resistant gloves or oven mitts.
Allow the frittata to cool for a few minutes before slicing and serving.
