Prepare the Filling:

In a bowl, crack the eggs and whisk them together with the milk (if using), salt, and pepper. In a skillet, heat a little oil or butter over medium heat. Add any optional vegetables like bell peppers, onions, or mushrooms, and cook until softened, about 3-4 minutes. Add the egg mixture and cook, stirring occasionally, until the eggs are scrambled and fully cooked. Remove from heat.

Assemble the Quesadillas:

Lay out your tortillas on a flat surface. On one half of each tortilla, sprinkle some shredded cheese, followed by a scoop of scrambled eggs. Add any optional cooked bacon or sausage. Top with a little more cheese, then fold the tortilla in half to create a half-moon shape.

Cook the Quesadillas:

Heat a large skillet or griddle over medium heat and lightly coat with butter or oil. Place the filled tortillas in the skillet and cook for 2-3 minutes per side, until golden brown and crispy, and the cheese is melted inside. You can press down lightly on the quesadilla with a spatula to help it crisp up.

Serve:

Once the quesadillas are done, remove them from the skillet and let them cool for a minute. Slice into wedges and serve with your favorite brunch sides like salsa, sour cream, guacamole, or hot sauce. Garnish with fresh cilantro or green onions if desired.