Make sure to carefully follow each step of the instructions for the best results :
- Preheat the oven.
Set the oven to 375°F. Make sure you have a 10-inch oven-safe skillet, ideally cast iron or stainless steel, so it can go directly from the stovetop to the oven. Having an oven-safe skillet is essential for frittatas since they start on the stove and finish in the oven. - Whisk the egg mixture.
In a large bowl, whisk together the eggs, heavy cream, salt, and pepper until light and well combined. Stir in the chives, dill, and parsley. Adding the herbs directly to the egg base is a common step in herb frittata recipes because it distributes the flavor evenly through every slice. - Sauté the vegetables.
Heat the olive oil and butter in the oven-safe skillet over medium heat. Add the leek or onion and cook for 3 to 4 minutes until softened. Stir in the garlic, asparagus, and peas and cook for another 2 to 3 minutes. Add the baby spinach last and let it wilt for 1 minute. This keeps the asparagus and peas tender without overcooking them before the eggs go in. - Pour in the eggs.
Reduce the heat to medium-low and pour the egg mixture evenly over the vegetables in the skillet. Let it cook on the stovetop for 2 to 3 minutes, without stirring, until the edges begin to set. Cooking the frittata briefly on the stovetop before transferring to the oven helps it set evenly all the way through. - Add the goat cheese and bake.
Scatter the crumbled goat cheese over the surface of the frittata and sprinkle with Parmesan if using. Transfer the skillet to the oven and bake for 12 to 15 minutes, until the eggs are fully set in the center and the top is lightly golden. The goat cheese softens and melts into the eggs as the frittata bakes, creating creamy pockets of tangy flavor throughout. - Rest and serve.
Let the frittata rest for 3 to 5 minutes before slicing. This helps it hold together cleanly when cut. Serve warm or at room temperature, garnished with a few extra fresh herbs on top.