Steps
1. Preheat your oven to 375°F (190°C).
2. In a skillet, heat the olive oil over medium heat. Add the sliced mushrooms and sauté until they are golden brown.
3. Add the diced tomato and cook for an additional 2 minutes.
4. In a bowl, whisk the eggs and season with salt and pepper. Pour the egg mixture over the vegetables in the skillet.
5. Sprinkle the shredded cheese on top and gently stir to combine.
6. Cook on the stovetop for 2-3 minutes until the edges start to set, then transfer the skillet to the oven.
7. Bake for 10-12 minutes, or until the frittata is puffed and cooked through.
8. Remove from the oven, let it cool slightly, and garnish with fresh basil if desired. Slice and serve warm.