Prepare rinsed quinoa according to package directions adding onions and garlic with quinoa.
Meanwhile, in medium skillet, sauté bacon until crispy; remove to clean paper towels to drain.
In large mixing bowl, combine milk and eggs; salt and pepper to taste. Whisk until well combined. Stir in cheeses, quinoa and bacon.
Transfer to a greased deep dish pie plate; sprinkle with additional cheese, if desired. Bake in a preheated 400°F oven 25 minutes or until set and golden brown. Cut into slices.