01 - Preheat the oven to 375°F.
02 - Heat the olive oil in an oven-safe 10-inch nonstick skillet over medium heat.
03 - Add the butternut squash and Brussels sprouts. Sauté for 6-8 minutes until slightly softened.
04 - Stir in the red onion and continue to cook for 3 minutes, until translucent.
05 - Add the roasted red peppers and spinach. Cook, stirring, until the spinach wilts, about 2 minutes.
06 - In a medium bowl, whisk together eggs, skim milk, salt, pepper, thyme, and smoked paprika until well combined.
07 - Pour the egg mixture evenly over the sautéed vegetables.
08 - Sprinkle the crumbled feta over the top, if using.
09 - Let cook undisturbed on the stove for 3-4 minutes, until the edges begin to set.
10 - Transfer the skillet to the oven and bake for 15-18 minutes, or until the center is just set and slightly puffed.
11 - Remove from oven and let cool for 5 minutes before slicing. Serve warm or at room temperature.