Step 1

Preheat oven to 350 degrees F., and prepare a baking sheet by lining it with a sheet of parchment.

Step 2

Heat skillet on stove top on medium heat. Put 1 tablespoon of olive oil. Add the minced onion and sauté until soft, about 3-4 minutes. Add spinach and mix well. It will take a few minutes for the spinach to warm up and soften so that it blends easily. Remove from heat and allow to cool for about 10 minutes.

Step 3

In a large bowl, beat eggs. Add remaining 2 tablespoons of olive oil and crumbled feta cheese. Combine cooled, cooked spinach mixture with egg mixture.

Step 4

Bake for 12-15 minutes until heated through and shells are lightly browned.