Heat 1 tablespoon olive oil in a large nonstick skillet over medium-high heat. Add the frozen hash browns in an even layer and cook undisturbed for 5 minutes until golden on the bottom. Flip and cook another 4-5 minutes until crispy and cooked through. Transfer to a plate and season with 1/4 teaspoon salt.

In the same skillet, add the remaining 1 tablespoon olive oil and the breakfast sausage. Break into small pieces with a wooden spoon and cook over medium heat until browned and cooked through, about 8-10 minutes. Transfer to the plate with the potatoes. Wipe out the skillet.

Whisk together the eggs, milk, remaining 1/2 teaspoon salt, and black pepper. Heat the skillet over medium-low heat, add the egg mixture, and cook slowly, stirring gently with a silicone spatula, until soft curds form and eggs are just set but still slightly glossy, about 5-6 minutes. Remove from heat immediately - they will continue cooking slightly.

Lay out 8 tortillas on your counter. Divide the eggs, sausage, potatoes, and cheese evenly among them, placing filling slightly below the center of each tortilla. Fold the bottom up over the filling, fold in the sides, then roll tightly from bottom to top. Place seam-side down on a baking sheet.

Wrap each burrito tightly in aluminum foil, then place all wrapped burritos in a gallon freezer bag. Freeze for up to 3 months. To reheat: unwrap from foil, wrap in a damp paper towel, and microwave on 50% power for 3 minutes, then full power for 1 minute until hot throughout. Or bake wrapped in foil at 350F for 25-30 minutes.