Preheat oven to 400°F. Then spray a 6-cup muffin tin generously with cooking oil.
Make the potato, turkey, & bean crust:
If using oats or flour for extra structure, start by mixing 3-4 tablespoons into the leftover potato burrito filling in a small bowl.
The mixture should hold together when pressed and not be loose or runny. If it’s still too wet, add another 1-2 teaspoons at a time until it reaches the right consistency.
Divide the filling evenly among the 6 muffin cups (about 2-3 tablespoons per cup).
Press the filling firmly into the bottom and slightly up the sides of each muffin cup to create a crust.
Bake for 18-20 minutes until the filling is set and slightly dried out. This creates a firm base that won’t mix with the eggs.
Then remove from the oven and let it cool for 3-5 minutes. Reduce oven temperature to 350°F.
While the crusts are baking, whisk together the eggs, milk, salt, pepper, and any optional seasonings in a bowl until well combined.
Stir in optional shredded cheese.
Carefully pour the egg mixture into each muffin cup over the potato crust, filling about ¾ of the way full (don’t overfill or the eggs may overflow).
Bake at 350°F for 18-22 minutes, or until the eggs are set and lightly golden on top. A toothpick inserted in the center should come out clean.
Let it cool for 3-5 minutes before carefully removing from the muffin tin using a butter knife or small spatula.