Preheat the oven to 375°F (190°C).

In a large skillet, heat olive oil over medium heat. Add the chopped onion and sauté until translucent, about 5 minutes.

Add the fresh spinach to the skillet and cook until wilted, about 3-4 minutes. Remove from heat.

Stir in crumbled feta, dill, parsley, salt, and pepper. Mix until well combined.

Lay one sheet of phyllo dough on a clean surface and brush it lightly with olive oil. Place a second sheet on top and brush it again.

Cut the layered phyllo into strips approximately 3 inches wide.

Place a tablespoon of the spinach filling at one end of each phyllo strip. Fold the corner over to form a triangle, then continue folding in a triangular shape to seal the filling inside.

Place the formed triangles on a baking sheet lined with parchment paper. Brush the tops with the remaining olive oil.

Bake in the preheated oven for 20-25 minutes until golden brown and crispy.

Remove from the oven and allow to cool slightly before serving.