Arrange a rack in the middle of the oven and heat to 400°F. Prepare space in the freezer for a baking sheet.

Combine the potatoes, peppers, and onions together in a medium bowl. Drizzle with the oil and 1/2 teaspoon of the salt, and toss to coat. Transfer to an even layer on a baking sheet and roast until the potatoes are tender, about 20 minutes.

While the veggies roast, whisk together the eggs, milk, and remaining 1/2 teaspoon salt until combined. Melt the butter in a 10-inch skillet (cast iron or nonstick would be ideal) over medium heat. Add the eggs and cook, stirring occasionally, until mostly set but still moist, 4 to 5 minutes. Remove from the heat.

Let the eggs and roasted vegetables cool while you set up an assembly station — the eggs and vegetables should be room temperature for best assembly. Tear off 12 squares of aluminum foil. Have your cheese and tortillas standing by. Place a tortilla on top of a piece of foil. Sprinkle 2 tablespoons of cheese onto the tortilla. Top the cheese with 1/4 cup roasted vegetables, followed by 2 heaping tablespoons of the scrambled eggs, and any extra toppings.

Roll the burrito tightly by folding the sides over the filling, then rolling from the bottom up.

Wrap the burrito tightly in the aluminum foil and repeat with filling and folding the remaining burritos. Freeze the burritos in a single layer on a baking sheet — they'll freeze faster and more uniformly this way. Store frozen burritos in a gallon-sized zip-top freezer bag for longer-term freezing.

Unwrap and microwave on high for 1 to 2 minutes, until warmed through, or heat in a regular or toaster oven at 350°F for 12 to 15 minutes.