Heat the skillet by placing a non-stick skillet over medium heat and adding a tablespoon of butter. Allow the butter to melt and become bubbly.

Crack one large egg directly into the skillet, sprinkle with salt and pepper, and cook until egg whites are set and yolk remains runny, about 3-4 minutes.

In the same skillet, lay a flour tortilla flat and sprinkle half of the shredded cheese evenly over it.

Place the fried eggs on top of the melted cheese tortilla. Add sliced avocado now if using.

Sprinkle the remaining cheese over the eggs and layer another tortilla, pressing down gently. Cook for 2-3 minutes until golden brown.

Flip the quesadilla carefully and cook for another 2-3 minutes until the second side is golden and cheese is melted.

Remove from heat, let cool slightly, slice into wedges and serve immediately with salsa or fresh herbs if desired.