Chop the vegetables into small, even pieces and set aside. Preheat the oven to 375°F (190°C).
Heat olive oil in a frying pan over medium heat; once shimmering, add the vegetables. Sauté until they soften and become fragrant, about 5 minutes, stirring occasionally.
In a mixing bowl, whisk the eggs until smooth and slightly frothy. Season with salt and pepper to taste.
Add the cooked vegetables and shredded cheese to the beaten eggs, gently folding them together to combine evenly.
Pour the mixture into an oven-safe baking dish, spreading it out evenly with a spatula.
Place the dish in the preheated oven and bake until the eggs are set and the top is lightly golden, about 20 minutes.
Remove the frittata from the oven and let it cool slightly before slicing into wedges.
Garnish with additional herbs if desired, then serve warm with your favorite sides.