Preheat the oven to 400ºF.2. Melt the butter in an ovenproof skillet over medium heat. Add the onion and sauté until tender and golden, 8 to ı0 minutes. Add the bell pepper and sauté for another 5 minutes. Add the spinach and cook for another minute, until just wilted.3. Crack the eggs into a large bowl, add the salt, and beat well with a fork. Pour the beaten eggs into the skillet and use the fork to press the vegetables down into the egg mixture so that the eggs cover the veggies completely. Crumble the chèvre over the top, then place the pan in the oven and bake until the top is set and lightly golden, ı0 to ı5 minutes.4. Cut into wedges and serve warm.