Cook sausage in large skillet over medium heat, stirring occasionally, until completely browned. Transfer to a paper towel-lined plate, leaving grease in skillet. You may add a little butter if there is too little grease in the pan.

Add garlic to the pan and cook over medium heat, stirring constantly, until fragrant, about 1 minute.

Add half the spinach to the pan and cook until wilted, about 30 seconds.

Add remaining spinach and cook until wilted and most of the liquid has evaporated, about 5 minutes. Season to taste with salt and pepper. Transfer to a paper towel-lined plate and wipe skillet out.

Melt butter in clean skillet over medium heat. In a small bowl, whisk eggs, salt and pepper to taste, and optional milk. Add to heated skillet, stirring constantly and cook until eggs are no longer watery, but still moist. Transfer to a plate.

Spread salsa over each tortilla. Divide spinach evenly over each of the 4 tortillas. Next, divide eggs and place on top of spinach and top with crumbled sausage.

Serve immediately with crumbled cotija or feta cheese, lime wedges, sliced green onions and cilantro.