Preheat your oven to 180°C (350°F). Lightly oil the skillet with 1 tablespoon of olive oil, spreading it evenly across the bottom.
In a mixing bowl, whisk the egg whites with a pinch of salt until soft peaks form, about 2-3 minutes, creating a light, airy foam.
While whisking, chop your bell peppers and sauté them in the skillet over medium heat until tender, about 3-4 minutes, until they smell sweet and look slightly charred around the edges.
Add the chopped spinach to the skillet and cook until wilted, about 1-2 minutes. Remove excess moisture with a paper towel if necessary.
Gently fold the sautéed vegetables and chopped herbs into the whipped egg whites, being careful not to deflate the fluffiness.
Pour the mixture into the prepared skillet, spreading it evenly. If desired, sprinkle with a little cheese for extra flavor.
Cook over medium-low heat until the edges start to set and turn golden, about 4-5 minutes, with gentle bubbling and a fragrant aroma filling the kitchen.
Transfer the skillet to the oven and bake for 12-15 minutes until the top is puffed, golden, and fully set, with no runny egg whites remaining.
Remove the skillet from the oven, squeeze a little lemon juice over the top, and let it rest for 2-3 minutes to settle.
Slice into wedges and serve warm, garnished with extra herbs if desired, enjoying the light, fluffy texture and fresh flavors.
