Follow these detailed, step-by-step instructions to assemble your perfect Spinach and Cheese Breakfast Quesadillas. The key is to prepare the filling first and then cook each quesadilla individually to ensure a hot, crispy, and perfectly melted result every time.

Step 1: Prepare the Vegetable Filling

The first step is to create the savory base for our quesadilla filling. This involves cooking down the aromatics and wilting the spinach to remove excess water, which is crucial for preventing a soggy final product.

1. Place a large non-stick skillet or pan over medium heat and add 1 tablespoon of butter or olive oil.
2. Once the butter is melted or the oil is shimmering, add the finely diced yellow onion. Sauté for 3-4 minutes, stirring occasionally, until the onion becomes translucent and soft.
3. Add the minced garlic to the skillet and cook for another minute until it is fragrant. Be careful not to let the garlic burn, as it can become bitter.
4. Add the fresh spinach to the skillet in batches. It will look like a lot at first, but it will wilt down significantly. Stir continuously until all the spinach has wilted, which should take about 2-3 minutes.
5. Continue to cook the spinach mixture for another minute to allow any excess moisture to evaporate. Season lightly with a pinch of salt and pepper.
6. Once cooked, transfer the spinach and onion mixture to a separate bowl and set it aside. Wipe the skillet clean for the next step.

Step 2: Cook the Scrambled Eggs

Next, we will prepare the fluffy scrambled eggs that will bind our filling together. The goal is to cook them until they are just set, as they will cook a little more inside the quesadilla.

1. In a medium-sized mixing bowl, crack the 6 large eggs. Add the optional 2 tablespoons of milk or cream, along with the remaining salt and pepper.
2. Whisk the eggs vigorously until the yolks and whites are completely combined and the mixture is light and slightly frothy.
3. Return the skillet to the stove over medium-low heat and add the remaining tablespoon of butter or oil.
4. Pour the whisked egg mixture into the skillet. Let the eggs sit for about 20-30 seconds until the edges just begin to set.
5. Using a rubber spatula, gently push the eggs from the edges toward the center, creating large, soft curds. Continue this gentle pushing and folding motion until the eggs are about 90% cooked. They should still look slightly wet and glossy.
6. Remove the skillet from the heat. Fold the cooked spinach and onion mixture back into the scrambled eggs. Stir gently to combine everything evenly.

Step 3: Assemble and Cook the Quesadillas

Now for the fun part: assembling and cooking the quesadillas to golden-brown perfection.

1. Keep the skillet on medium-low heat. If the pan is dry, you can add a very thin layer of butter or cooking spray.
2. Place one flour tortilla flat in the skillet.
3. Sprinkle about ¼ cup of the shredded cheese blend over the entire surface of the tortilla.
4. Spoon one-quarter of the spinach and egg mixture evenly over one half of the tortilla.
5. Sprinkle another ¼ cup of shredded cheese on top of the egg mixture. The cheese on both the bottom and top will act as a delicious “glue” to hold the quesadilla together.
6. Carefully fold the empty half of the tortilla over the half with the filling. Use a spatula to gently press it down.
7. Cook for 2-4 minutes on the first side, until the bottom of the tortilla is golden brown and crispy and the cheese has begun to melt.
8. Carefully flip the quesadilla using a wide spatula. Cook for another 2-3 minutes on the second side until it is also golden brown and the cheese is completely melted and gooey.
9. Slide the cooked quesadilla onto a cutting board. Let it rest for a minute before slicing it into wedges. This helps the filling set and prevents the melted cheese from spilling out immediately.
10. Repeat the process with the remaining tortillas and filling until all four quesadillas are cooked.