01 - Set the oven to 375°F and prepare for baking.
02 - In a large ovenproof skillet, warm 1 tablespoon of oil over medium heat. Add the sliced red onion and diced red bell pepper; cook for 3 minutes until softened.
03 - Add the diced zucchini and continue cooking for 2 minutes. Stir in the chopped spinach and cook until wilted.
04 - If desired, incorporate shredded chicken and cherry tomatoes. Stir thoroughly then remove skillet from heat.
05 - In a separate bowl, whisk together eggs, sea salt, black pepper, smoked paprika, parsley, and chives until well combined.
06 - Pour the egg mixture evenly over the vegetables in the skillet. Tilt the pan to ensure full coverage.
07 - Drizzle the remaining 1 tablespoon of oil evenly over the top.
08 - Place the skillet in the preheated oven and bake for 18 to 22 minutes until the center is just set and the surface has a light golden color.
09 - Allow to cool for 5 minutes before slicing. Serve warm or at room temperature.