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Sweet Potato and Spinach Frittata Recipe with Caramelized Onions

This sweet potato frittata with spinach and caramelized onion makes a beautiful, nutritious breakfast (or lunch or dinner). Shredded sweet potato forms a naturally gluten-free crust, while eggs, spinach, and tender caramelized onions create a flavorful, protein-rich filling.

Two plates with slices of sweet potato frittata sprinkled with parsley.

This recipe first appeared in September 2014 and has been a favorite ever since. After retesting, rephotographing, and refining a few tips, the recipe is the same but clearer and easier to follow.

It’s easy to forget older posts when new ideas keep coming, but this sweet potato crust frittata deserves a repeat performance. It’s simple to make, stores well in the fridge, and is versatile enough to serve the whole family—cut into slices for breakfast, pack for lunch, or add to a toddler’s plate to sneak in vegetables and protein.

A skillet with caramelized onions, showing the dark and smooth texture once they are finished.

Make a batch ahead and enjoy it warm, cold (try with hot sauce), or chopped into other dishes. The sweet potato crust keeps this frittata naturally gluten-free, and if you skip the cheese it’s also Whole30-compliant.

How to Make a Sweet Potato Crust

A bowl full of egg and spinach mixture.

Shredding the sweet potato yields a soft, compact base rather than a crisp hash. To build the crust, shred the potato, spread it evenly in a greased baking dish, and bake it covered to soften. After baking, press the sweet potato into the pan to form an even crust and gently press it up the sides if you want a sturdier edge.

A baking dish with layers of sweet potato, eggs, spinach, and caramelized onions, ready to be baked.

Once your onions are deeply caramelized, whisk the eggs with seasonings, spinach, and a bit of parmesan if you’re including cheese. Pour the egg mixture into the sweet potato crust, top with the onions (and extra parmesan if desired), and bake covered until set. Remove the cover and finish at a lower temperature to lightly brown the top and ensure the center is firm.

A slice of sweet potato frittata.

Tips for Success

  • Gluten-free base: Shredded sweet potato forms a naturally gluten-free crust—no flour required.
  • Whole30 / Paleo: Omit the parmesan to make this compliant with Whole30 or strict paleo eating.
  • Customizable filling: Use whatever vegetables you have on hand. Red peppers, broccoli, mushrooms, or kale all pair well with eggs.

Ingredients

Sweet Potato Crust

  • 1 teaspoon olive oil
  • 1 large sweet potato, shredded (peeling optional)
  • Sea salt and freshly ground black pepper, to taste

Frittata Filling

  • 2 teaspoons olive oil
  • 1 onion, thinly sliced
  • Sea salt, to taste
  • 8 eggs
  • 1/2 cup spinach (frozen and thawed, or about 4 cups fresh chopped)
  • 1/3 cup parmesan cheese, shaved or grated (omit if desired)
  • 1/2 teaspoon Italian seasoning
  • 1/4 teaspoon sea salt
  • Freshly ground black pepper, to taste

Instructions

  1. Preheat the oven to 425°F (220°C).
  2. Shred the sweet potato using a food processor or box grater. Coarsely shredded pieces work well.
  3. Grease the bottom of a baking dish with 1 teaspoon olive oil. Spread the shredded sweet potato evenly and season lightly with sea salt and black pepper.
  4. Cover the dish tightly with foil and bake for 30 minutes to soften the sweet potato.
  5. While the sweet potato bakes, thinly slice the onion and cook it in 2 teaspoons olive oil over medium-low heat. Stir occasionally until the onions are very soft and caramelized. If the pan becomes dry, add a few tablespoons of water rather than more oil. Season with sea salt and set aside.
  6. Whisk the eggs in a bowl and stir in the thawed or chopped fresh spinach, parmesan (if using), Italian seasoning, 1/4 teaspoon sea salt, and black pepper.
  7. When the sweet potato is done, remove the dish from the oven and allow it to cool for 5–10 minutes so you can handle it safely. Loosen the foil and, using a dish towel to protect your hand, press and compress the sweet potato into an even crust, pressing some up the sides if you like.
  8. Pour the egg and spinach mixture into the sweet potato crust and scatter the caramelized onions on top.
  9. Cover the dish tightly with foil and return it to the oven at 425°F for about 20 minutes.
  10. Remove the foil, lower the oven to 320°F (160°C), and bake another 10–15 minutes until the center is set and the eggs are firm. Timing will vary by oven.
  11. Remove from the oven, sprinkle additional parmesan if desired, and let rest a few minutes before slicing into 8 pieces.

Notes

Substitute any vegetables for the spinach and caramelized onion. Bell peppers, broccoli, mushrooms, or greens like kale work well. You can also try white potatoes instead of sweet potato for a different flavor and texture. Store slices in the refrigerator for easy reheating.

Recipe Details

Course: Breakfast. Cuisine: American. Servings: 8 slices. Prep time: about 30 minutes. Cook time: roughly 1 hour 30 minutes (including baking steps). Total time: about 2 hours including cooling and resting.

Nutrition (per slice, approximate)

Calories: 112 kcal | Carbohydrates: 5 g | Protein: 7 g | Fat: 6 g | Saturated Fat: 2 g | Cholesterol: 166 mg | Sodium: 212 mg | Potassium: 146 mg | Sugar: 1 g | Vitamin A: 2750 IU | Vitamin C: 1.9 mg | Calcium: 86 mg | Iron: 1 mg

The whole frittata baked and still in the baking dish.

If you try this sweet potato frittata, feel free to mention it on social media or tag your photos so others can discover a naturally gluten-free, veggie-packed egg dish that’s perfect for meal prep and family-friendly meals.