Step 1: Prepare the Vegetables
Slice the Potatoes and Onions: Peel and thinly slice the potatoes and onion. A mandoline slicer can help achieve uniform slices, making for even cooking.
Soak the Potatoes: To remove excess starch, soak the potato slices in cold water for about 10 minutes. This will help keep them crispy.
Step 2: Cook the Potatoes and Onions
Heat the Oil: In a large, oven-safe skillet, heat the olive oil over medium heat.
Sauté the Onions: Add the sliced onions to the skillet and sauté for about 5 minutes until they start to soften.
Add the Potatoes: Drain and pat dry the potato slices. Add them to the skillet with the onions. Season with salt and pepper.
Cook Until Tender: Cover the skillet and cook for about 15-20 minutes, stirring occasionally, until the potatoes are tender but not falling apart.
Step 3: Prepare the Egg Mixture
Whisk the Eggs and Milk: In a mixing bowl, whisk together the eggs, milk, and a pinch of salt and pepper. If you’re adding cheese, mix it in at this stage.
Combine with Vegetables: Once the potatoes and onions are tender, pour the egg mixture evenly over the vegetables in the skillet. Let it cook for 2-3 minutes without stirring, until the edges start to set.
Step 4: Cook the Frittata
Finish Cooking: Reduce the heat to low, cover the skillet, and cook for another 10-15 minutes. The frittata is done when the eggs are set but still slightly soft in the center.
Broil for a Golden Top: For an extra touch, you can place the skillet under the broiler for 2-3 minutes to achieve a golden top. Just keep an eye on it to prevent burning!
Step 5: Serve
Let it Stand: Allow the frittata to cool for about 5 minutes before slicing it into wedges.
Garnish: Optionally, sprinkle fresh herbs on top for added flavor and presentation.