Step 1: Preheat the oven (optional): If you plan to bake and eat the burritos immediately, preheat the oven to 375°F (190°C). This step is not necessary if you are freezing the burritos for later.

Step 2: Sauté the vegetables: Heat the olive oil in a medium/large nonstick skillet over medium heat. Once the oil is hot and shimmering, add the chopped vegetables. Cook, stirring frequently, until the vegetables are softened, about 4 minutes. This step helps to bring out the natural sweetness of the vegetables and adds a depth of flavor to the burritos. Transfer the sautéed vegetables to a clean medium-sized bowl.

Step 3: Cook the sausage: Add the breakfast sausage or Italian sausage (removed from its casings) to the same skillet. Cook, crumbling the sausage with a spoon or spatula, until it is browned and fully cooked. Ensure that there are no pink pieces remaining. Transfer the cooked sausage to the bowl with the vegetables, leaving any excess grease in the pan.

Step 4: Prepare the eggs: Crack the eggs into a medium mixing bowl. Add the salt. Whisk the eggs vigorously until they are completely combined and uniform in color. This ensures that the eggs will cook evenly and have a light, fluffy texture.

Step 5: Cook the eggs: Wipe out the skillet and add the butter. Heat over medium heat until the butter is melted, coating the bottom of the pan evenly. Pour the whisked eggs into the pan and immediately reduce the heat to medium-low. This prevents the eggs from cooking too quickly and becoming rubbery. Let the eggs cook without stirring for about 30 seconds. Then, using a rubber spatula, gently and slowly scrape across the bottom and around the edges of the pan as the eggs cook. This technique creates soft, creamy curds of scrambled eggs. Continue scraping across different areas of the pan and in different directions to prevent any bits of egg from drying out. As the eggs cook, gently fold them to ensure even cooking. Once the eggs are cooked to your desired consistency (slightly moist is ideal, as they will continue to cook in the burrito), turn off the heat.

Step 6: Combine the fillings: Add the cooked eggs to the bowl with the sausage and vegetables. Stir gently to mix everything together evenly. This combines all the delicious flavors and textures into one cohesive filling.

Step 7: Assemble the burritos: Warm the tortillas slightly in a dry skillet or microwave to make them more pliable and prevent them from tearing. To assemble each burrito, place approximately 1/8 of the egg/sausage/veggie mixture on top of the tortilla. Position the filling in a line slightly off-center for easier wrapping. Sprinkle about 1/4 cup of shredded cheese on top of the egg mixture.

Step 8: Wrap the burritos: Tightly wrap each tortilla burrito-style. To do this, fold in the sides of the tortilla towards the center, then fold the bottom edge up and over the filling. Tuck the bottom edge under the filling tightly, and roll the burrito away from you until it is completely sealed.

Step 9: Cook or Freeze: The burritos can be eaten as is, baked to melt the cheese and crisp the tortillas, or frozen for later use.

Step 10: Optional Baking (if eating immediately): Place the burritos seam-side down on a parchment paper-lined baking sheet. Bake in the preheated 375°F (190°C) oven for 5-10 minutes, or until they are warmed through and lightly browned. This step will melt the cheese and create a crispy tortilla. Serve immediately.

Step 11: Freezing for Later: To freeze the burritos, first flash-freeze them by placing them on a baking sheet in the freezer for about 2 hours. This prevents them from sticking together once they are transferred to a bag. Once the burritos are frozen solid, transfer them to a zip-top plastic bag and store them in the freezer for up to 1 month.

Step 12: Thawing and Heating a Frozen Burrito: To thaw a frozen burrito, place it in the refrigerator overnight. To reheat, microwave on high power for 30-45 seconds to start warming the center of the burrito. Then, transfer the burrito to a 350°F (175°C) oven for 10 minutes, or until it is fully heated through. Alternatively, you can fully reheat the thawed burrito in the microwave. Using the oven will give you a crispier tortilla, while microwaving will result in a chewier tortilla.