Heat oven to 350°F. Rub 13 x 9 (quarter rimmed sheet pan) with avocado oil or olive oil (don't forget to get the sides!). Next, line the baking sheet with parchment paper and push down to press out bubbles. Spray again, yes again!, with cooking spray (I use avocado oil spray with no added ingredients!).
Make sausage or bacon as directed and set aside.
In a large bowl whisk together eggs, milk, garlic granules, salt and pepper.If adding veggies (see note, ideally pre-cooked veggies!), roast them, then combine any well-chopped ingredients into your egg mixture, and whisk until combined.
Pour the mixture into the prepared baking sheet pan and carefully transfer to the oven to avoid eggs spilling!
Bake for 15-20 minutes, or until the eggs are set and bit puffy and just set.
Let cool before slicing. Cut into squares (or rounds- a wide mason jar lid works great or a round cookie cutter). Spread English muffins with butter (optional) and place an egg round on each one.
Add cheese, breakfast meat, then wrap each sandwich separately in foil or parchment paper, place wrapped sandwiches into a ziplock bag, then store in the refrigerator or the freezer. Refrigerate (4-5 days) or freeze (3-6 months ideally!). See notes for how to reheat!