Preheat the oven to 375°F (190°C).
In a medium bowl, whisk together the eggs, whole milk, salt, and black pepper until well combined.
Heat olive oil in a skillet over medium heat. Add diced onion, green bell pepper, and red bell pepper. Sauté for 3-4 minutes until vegetables are softened.
Add the cooked and crumbled breakfast sausage to the skillet with the vegetables. Stir to combine and heat through for 2 minutes. Remove from heat.
Pour the egg mixture into the skillet with the sausage and vegetables. Cook, stirring gently, until the eggs are just set but still soft, about 3-4 minutes. Remove from heat.
Place the pre-made pizza crust on a baking sheet or pizza stone.
Spread the cooked egg, sausage, and vegetable mixture evenly over the pizza crust.
Sprinkle shredded mozzarella and cheddar cheese evenly over the top.
Bake the pizza in the preheated oven for 15-20 minutes, or until the cheese is melted and bubbly and the crust is golden brown.
Remove the pizza from the oven and let it cool completely on a wire rack.
Once cooled, wrap the pizza tightly in plastic wrap and then aluminum foil. Label and freeze for up to 3 months.
To reheat, remove the wrapping and bake the frozen pizza at 375°F (190°C) for 15-20 minutes or until heated through and cheese is bubbly.