Heat 1 tablespoon oil in a large skillet over medium.

Sauté 1 diced bell pepper and ½ diced onion 5-6 minutes until softened and lightly caramelized.

Push vegetables aside; crack 4 eggs into other side.

Scramble eggs until just set and 160°F; mix with vegetables and transfer to a plate.

Wipe out the skillet. Use 1/2 tablespoon butter for each quesadilla, melting it over medium heat.

Place one large flour tortilla in the skillet.

On half of a tortilla put one quarter of the egg filling and 1/4 cup cheddar.

Fold tortilla over filling; press gently with a spatula.

Cook 3-4 minutes until bottom is golden brown and crispy.

Carefully flip; cook another 3 minutes until second side is golden and cheese fully melted.

Remove to a cutting board and repeat with remaining tortillas and fillings.

Cut into wedges and serve with optional salsa and sour cream.