First, gather all your ingredients, and take a moment to appreciate what each will add to your frittata. Slice the leeks and spinach, and mince the garlic. This is like painting; preparation is key to a beautiful final product.

In a large skillet, heat up the olive oil and butter on medium heat. Once melted, toss in the sliced leeks and minced garlic. Cook until they are soft and fragrant, around 5–7 minutes. The leeks should turn tender, and they will bring a light sweetness to your dish.

As the leeks become translucent, stir in the spinach. You only need to cook it until it wilts—about 2 minutes will do the trick. This adds not just flavor but also a vibrant color.

In a bowl, whisk together the eggs, egg whites, milk, dill, salt, and pepper. Make sure everything blends well, and don’t be shy about seasoning. You want the flavors to shine.

Pour the egg mixture over the sautéed leeks and spinach in the skillet. Stir gently to distribute the vegetables evenly, and sprinkle the crumbled goat cheese over the top. At this moment, your kitchen should smell amazing.

Cook for around 4–5 minutes on the stove, gently shaking the pan occasionally to ensure the eggs don’t stick. You want the edges to set while the center remains slightly runny.

Now preheat your oven to 375°F (190°C). Transfer the skillet to the oven and bake for another 10–15 minutes, or until the frittata is set in the middle and slightly browned on top. If your skillet is oven-proof, great! If not, carefully transfer it to a greased baking dish.

Once cooked, pull it out of the oven and let it cool for a few minutes. Slice into wedges, and enjoy warm or at room temperature. This dish is beautiful enough for company and satisfying enough for a quiet night in.