To prepare a southwest egg and cheese boats recipe, you'll first need to prepare the ingredients for the recipe. First, preheat the oven to 375 degrees F (190 degrees C) and prepare your oven rack to the lowest setting. Using an electric mixer, beat the egg whites on medium-high speed until stiff peaks form. Gradually add the milk, beating well after each addition. Add salt and pepper to taste. Fold in the cheese until the mixture is evenly coated. Pour the batter into the prepared pan and bake for 20 to 25 minutes or until browned and set. Serve with sour cream and salsa.