1. In a medium-size skillet, melt the butter and sauté the onion over medium-low heat until almost tender, approximately 5 minutes.

2. Add sausage, bell pepper and jalapeño (if using), and continue sautéing over medium-heat until the sausage is nicely browned and the bell pepper is softened.

3. While the sausage mixture is cooking, combine the eggs with the milk, cheese, salt and pepper in a medium-size bowl, and beat well.

4. Pour the egg mixture into the pan. Once the egg has begun to set, use a rubber spatula to occasionally lift and fold-over the ingredients until large curds start forming. Continue this action, cooking until eggs are thickened but still moist (about 3 to 5 minutes). Sprinkle with chopped cilantro.

5. Serve with salsa, avocado slices, sour cream and warm tortillas.