In a medium skillet over medium heat, cook the bacon until it’s crispy, which should take about 10 minutes. Use a slotted spoon to transfer the bacon to a paper towel-lined plate. Leave about 1 tablespoon of grease in the skillet for later use.
Return the skillet to medium heat and add the mushrooms and bell peppers. Cook until the mushrooms turn golden and the bell peppers soften, approximately 5 minutes. Season with salt and pepper. Add them to the plate with the bacon.
In a small saucepan over medium heat, combine the water and milk and bring it to a boil. Stir in the oats and continue boiling until they thicken and become soft, which should take about 5 minutes. Stir in the cheddar cheese and most of the green onions, keeping some aside for garnish. Season with salt and pepper to your liking.
Return the skillet to medium-low heat and add 2 tablespoons of the reserved bacon grease. Crack the eggs into the skillet and cook until the whites are set but the yolks are still runny, about 3 to 4 minutes. Tilt the pan carefully and spoon the grease over the eggs to help cook the tops. Season with salt and pepper.
Divide the oatmeal between two bowls and top each with an egg, bacon, mushrooms, and peppers. Sprinkle with the reserved green onions and more cheddar cheese. Enjoy your savory breakfast treat!