In a large skillet (I use a large cast iron skillet), over medium-high heat, brown the sausage for 5 minutes. Make a well in the center of the skillet. Add the bell pepper and sweet onion and cook for 1 minute. Stir the vegetables into the ground sausage. Saute the veggies, mixed with the sausage, until the onions are translucent (about 3-4 minutes). Strain the fat from the sausage and veggies, then place the mixture in a bowl and set aside.In the same skillet, melt the butter. Whisk the eggs and milk together. Add salt and pepper to taste. Pour the eggs into the skillet and scramble until the desired consistency. Remove the eggs from the heat. Add the sausage mixture to the eggs, gently stir to combine the ingredients.To assemble the burritos, place a few tablespoons of shredded cheese (or 1 slice) in the center of each tortilla. Add the egg and sausage mixture. Fold the sides into the center of the tortilla and then roll into a burrito. The burritos can be individually wrapped in parchment paper or foil; or simply place the burritos in a Ziploc bag (my preferred method).