In a large nonstick skillet over medium-high heat, heat half of the oil to shimmering. Add the peppers and onions and cook until tender. Remove to a bowl and keep warm.
Add the second half of the oil to the pan and heat to shimmering. Fry the potatoes in the oil till lightly browned and cooked through stir in the cooked sausage meat and heat through. Add potatoes and sausage to the vegetable mixture and combine. Set aside to keep warm.
In a medium bowl, toss the shredded cheese with the cornstarch. In a small heavy-bottomed saucepan, melt the butter. Add the canned tomatoes and green chiles and cook to heat through and drive off some of the liquid. Stir in the evaporated milk and heat to a simmer, then add the cheese and cornstarch mixture. Stir well and cook until fully melted and combined in a cohesive smooth sauce. If your sauce is too thick, stir in an extra tablespoon or two of water. Hold the sauce warm in a double boiler or water bath until service.
In a large bowl, beat the eggs with a fork until well blended, then add the grated butter, mixing until well combined. The butter will emulsify into the eggs and keep them fluffy and tender, even when cooked through.
Heat a nonstick skillet over medium-low heat. Spray with nonstick spray. Pour the egg and butter mixture into the pan. Using a heat-proof rubber spatula to scramble the egg mixture until firm throughout with no visible egg liquid remaining, and large curds have formed. Season to taste with salt and pepper.
Stir the potato mixture into the eggs, followed by the shredded cheeses. Keep warm.
In the center of each large tortilla place about a cup of the egg mixture in a rectangle. Bring the bottom of the tortilla over the eggs and tuck around filling. Tuck sides of tortilla in and roll up burrito style. Secure with a toothpick.
Deep fry or pan fry in peanut oil until crispy, remove the toothpick and serve hot with about ½ cup of the cheese sauce.
Note: Do not let uncooked egg mixture remain at room temperature for longer than one hour (including preparation and service time).