In a 12 inch oven-safe skillet, (I used a cast iron skillet) cook the sausage, onion, and peppers together over medium heat. Break up the sausage with your cooking utensil as it cooks so that there are no large chunks. Cook these until the sausage is browned and the onion & peppers are tender.
While those cook, break the eggs into a mixing bowl. Add in the water, mustard, basil, salt, and pepper. Whisk these together until the eggs are frothy.
When the sausage is browned, turn off the stove. Spread the sausage mixture evenly across the inside of the skillet.
Pour the egg mixture over the sausage mixture
Slide the skillet into the oven and bake for 25-30 minutes, or until the eggs are set and the top is just golden.
Remove the skillet from the oven and let it rest for 5 minutes