Preheat oven to 350°F (177°C). Line a 12-cup muffin tin with paper liners or grease with nonstick spray.
In a skillet over medium heat, cook the sausage until browned and fully cooked, breaking it into crumbles. Drain excess grease and set aside.
In a large mixing bowl, whisk the eggs.
Stir in the shredded cheese, green onions, cooked sausage, Bisquick mix, garlic powder (if using), and black pepper. Mix until just combined.
Spoon the mixture into the muffin cups, filling each about 3/4 full.
Bake for 18-22 minutes or until the tops are golden brown and a toothpick inserted in the center comes out clean.
Let muffins cool in the pan for 5 minutes before transferring to a wire rack.
Serve warm or store in an airtight container in the fridge for up to 5 days. Muffins can also be frozen for up to 3 months.
