Preheat oven to 350ºF and spray a 12-cup, nonstick muffin tin with cooking spray.
Peel 2 medium red potatoes and then shred with a cheese grater. Place shredded potato on top of a thin rag, cheesecloth, or paper towel and squeeze out as much excess moisture as possible. Place into a snall bowl and season with garlic powder, salt, and pepper. Then, spread evenly among the 12 cups.
Chop 12 fully-cooked breakfast sausage links and then add to the top of shredded potatoes.
In a medium bowl, whisk together eggs and milk. Then, pour egg mixture evenly on top of veggies in order to fill each cup around 3/4 of the way full. Use a fork or knife to mix in order to make sure the veggies are evenly distributed within the egg.
Season the top of each egg cup with salt and pepper, to taste, and then sprinkle on cheese.
Bake at 350ºF for around 18-22 minutes.