A hearty frittata loaded with savory sausage, vegetables, and melted cheese delivers a high protein, family-style brunch in one pan. This versatile dish works perfectly for meal prep and intermittent fasting schedules.
Preheat oven to 375°F. Prepare a 10-inch oven-safe skillet by heating olive oil over medium heat, making sure oil coats the whole pan.
Add the sausage to the heated skillet and cook for 6-8 minutes, breaking it up and stirring occasionally until browned and cooked through.
Stir in diced onion and red bell pepper; sauté for 4-5 minutes until the vegetables are softened. Add spinach and cook for another minute until just wilted.
In a separate bowl, whisk the eggs with salt, pepper, and oregano until fully blended. Pour egg mixture evenly over the cooked sausage and vegetables in the skillet.
Sprinkle cheddar cheese over the top. Transfer skillet to preheated oven and bake for 18-20 minutes, or until the eggs are just set and the center no longer jiggles. Cool for 5 minutes, slice, and serve.