Cook the bacon: In a pan over medium heat, cook bacon until crispy. Remove and set aside.
Sauté the veggies: In the same pan, add diced onion and bell pepper. Cook for 2–3 minutes until softened.
Scramble the eggs: Whisk eggs with milk, salt, and pepper. Pour into the pan and stir gently until just cooked.
Assemble the quesadilla: Place a tortilla in a clean pan. Add half the cheese, the scrambled eggs, bacon pieces, and top with more cheese. Cover with the second tortilla.
Toast until golden: Cook for 1–2 minutes on each side until golden brown and crispy. Slice into quarters and serve hot with salsa or avocado.