This substantial frittata uses thin roasted potatoes as a crisp base, then adds spinach and eggs for a breakfast that slices cleanly.

Equipment

• 10-inch oven-safe skillet
• Mixing bowl and whisk
• Mandoline or sharp knife
• Food thermometer

Ingredients

• 12 oz / 340 g Yukon Gold potatoes, ⅛-inch / 3 mm slices
• 1½ tablespoons / 22 ml olive oil
• 1 small onion, thinly sliced
• 2 packed cups / 60 g spinach
• 8 large eggs
• ⅓ cup / 80 ml milk
• ½ teaspoon salt
• ¼ teaspoon black pepper
• ⅓ cup / 35 g grated Parmesan

Preparation

• Heat oven to 400°F / 200°C.
• Slice potatoes evenly and pat dry.

Step-by-step directions

1. Coat potatoes with 1 tablespoon oil and arrange in overlapping layers in skillet. Bake 15 minutes.
2. Cook onion in remaining oil over medium heat 5 minutes; add spinach for 1 minute.
3. Whisk eggs, milk, salt, pepper, and half the cheese.
4. Spread vegetables over potatoes and pour egg mixture evenly.
5. Top with remaining cheese and bake 16–20 minutes.
6. Verify the center reaches 160°F / 71°C, then rest 8 minutes before slicing.

How to tell it is ready

The center is set, the edges are lightly browned, and the potatoes pierce easily.

Substitutions and variations

• Use Swiss cheese instead of Parmesan.
• Replace spinach with cooked, well-drained kale.
• Add ½ cup cooked mushrooms after their moisture evaporates.

Common problems

• Raw potatoes: slices were too thick or first bake was shortened.
• Rubbery eggs: frittata baked too long.
• Sticking: skillet was not coated before layering potatoes.

Allergen and safety notes

Contains eggs and milk. Use an oven-safe skillet and protect the hot handle. Egg dishes should reach 160°F / 71°C.

Storage and reheating

Refrigerate within 2 hours and use within 3–4 days. Reheat portions to 165°F / 74°C.

Serving ideas

Serve warm with tomatoes or a simple green salad.

A short rest firms the slices without additional cooking.