Instructions

Crumble the Cotija cheese to get 2 ounces, and grate Mozzarella (or use pre-grated Mozzarella like I did.) Slice the green onion.
Beat eggs (with the milk or half-and-half if using) until the whites and yolks are well combined.
Adjust the oven rack so it’s about 4-5 inches under the broiler and turn broiler on.
Heat the oil in a heavy oven-proof frying pan over medium-low heat.
When the pan feels hot when you hold your hand over it, add the eggs, season with Spike Seasoning and fresh-ground black pepper, and let eggs cook for about 2 minutes, just until they’re starting to look cooked on the edges. (I usually take a rubber scraper and run it around the edges, but it’s probably not really necessary!)
Add the grated mozzarella and sliced green onion and cook about 5 minutes more, or until the eggs look like they’re cooked about half-way through. (Actual cooking time will depend on your pan and how hot the medium-low setting is on your stove. Turn to low if it seems like the eggs are cooking too quickly.)
Slice the avocado while the eggs are cooking.
When eggs are cooked about half-way through, lay the avocado slices over and sprinkle with the Cotija cheese.
Cover the pan with the lid and cook about 3 minutes more, or until the eggs look like they’re nearly cooked through and the Cotija is starting to melt.
Remove lid, put the frittata under the broiler and cook about 2 minutes more, or the eggs are firm and cheese is melted and the top of the frittata is nicely browned. (Watch it carefully; it’s easy to get it too brown under the broiler!)
Serve hot.