Fluffy Vegetable Frittata

Preheat the oven to 180 °C. In a large bowl, whisk together the eggs, milk (or yogurt), crushed garlic, salt and pepper. Whisk just until the mixture is smooth and slightly frothy, but don't overdo it, so the frittata doesn't deflate too much.

Heat the olive oil in a cast-iron skillet over medium heat. Add the onion and pepper and sauté for 3–4 minutes until softened. Add the zucchini and sauté for another 3 minutes. Important: The zucchini should release water and turn slightly golden, otherwise the frittata will be watery. Finally, stir in the spinach and cook just until wilted (about 30 seconds).

Spread the vegetables evenly in the skillet. Pour the egg mixture over them. Tilt the skillet slightly so the eggs flow between the vegetables. Sprinkle crumbled feta cheese on top. Leave on the stove for 1–2 minutes so the edges of the eggs set slightly (become lighter in color).

Carefully transfer the skillet to the preheated oven and bake for 10–12 minutes. The frittata is done when the center is "set" – when the skillet is gently shaken, it shouldn't jiggle like liquid but should remain firm. Be careful not to overbake it, as it can become dry. If you don't have a cast-iron skillet, transfer the mixture to a smaller oven-safe dish before baking.

Remove from the oven and let rest for 5 minutes (this makes it easier to cut). Sprinkle with fresh parsley or chives, cut into triangles and serve warm or cold.