In a medium bowl, whisk together the eggs, salt, and pepper until well combined.

In a skillet over medium heat, melt the butter. Add the diced bell pepper and onion, sautéing for about 3-4 minutes until softened.

Pour the whisked eggs into the skillet with the vegetables. Cook, stirring gently, until the eggs are fully cooked but still soft, about 2-3 minutes. Remove from heat.

Lay one tortilla flat in the skillet. Sprinkle half of the cheese over the tortilla, then add the cooked egg mixture on top. Sprinkle the remaining cheese over the eggs and top with the second tortilla.

Cook the quesadilla over medium heat for about 3-4 minutes until the bottom tortilla is golden brown and the cheese begins to melt. Carefully flip the quesadilla using a large spatula and cook for an additional 3-4 minutes on the other side.

Remove from the skillet and let it cool for a minute before slicing into wedges. Serve with sour cream and salsa if desired.