Preheat oven to 350°F. Line a baking sheet with parchment paper.
In a skillet, heat olive oil over medium heat. Sauté green onions for 1–2 minutes until softened. Add chopped spinach and cook until wilted, about 2–3 minutes. Season with salt and pepper. Let cool slightly.
In a large bowl, mix together the egg whites, sautéed spinach mixture, almond flour, baking powder, and feta cheese. Stir until the mixture holds together. If needed, add a teaspoon of water or olive oil.
Form the mixture into 6 biscuit-sized rounds or drop by spoonfuls onto the baking sheet.
Bake for 20–25 minutes, or until edges are lightly golden.
Cool slightly before serving.
