Step 1

Preheat your oven to 400°F (205°C).

Step 2

In a large (around 10-inch) cast iron pan or oven-safe skillet, add olive oil to generously coat the entire pan. Heat the oil on your stovetop using medium heat and then add the onions, diced raw sweet potatoes, and asparagus. Cook until the ingredients are tender, stirring occasionally to prevent burning — around 8–10 minutes.

Step 3

Once the ingredients are tender, remove the pan from heat.

Step 4

In a large mixing bowl, whisk the eggs and then add in the chopped herbs, salt, pepper, and 3/4 of the shredded cheese. Whisk until blended.

Step 5

Pour the egg mixture into the pan, covering the vegetable mixture. Sprinkle the remaining shredded gruyère on top of the mixture.

Step 6

Slide the pan into the oven and bake on the middle rack for around 20 minutes, or until puffy, golden brown, and fully cooked through. Be sure to monitor the frittata while it's cooking. It may cook quicker than expected.

Step 7

Remove the frittata from the oven and let cool before slicing.

Step 8

Serve it with a side of fruit, like berries, or sliced avocado for an extra dose of nutrients.