Serve extra salsa on the side with bagel chips, or store in an airtight container in the refrigerator for up to a week. To make the burritos in the microwave: Place the sausage pieces in a microwave-safe container and cover with a damp paper towel to keep from drying out. Cook on high power for 2 minutes, or until heated through. Add the egg-butter mixture to another microwave-safe bowl and cook for 4 minutes, stirring halfway through. Place the tortillas on a plate, cover with a damp paper towel and an inverted plate, and cook on high for 15 seconds, or until softened. Build burritos as per the recipe.