In a large skillet, heat olive oil over medium heat. Add onion and garlic, sauté until softened.

Add chopped spinach, cook until wilted. Remove from heat and let cool.

In a mixing bowl, combine cooled spinach mixture with feta cheese, beaten egg, salt, pepper, and nutmeg.

Preheat the oven to 375°F (190°C).

Lay one sheet of phyllo dough on a clean surface, brush with melted butter. Layer another sheet on top and brush again.

Cut the layered phyllo into strips about 3 inches wide.

Place a tablespoon of filling at one end of each strip. Fold the corner over to form a triangle, then continue folding to the end of the strip.

Place the triangles on a baking sheet lined with parchment paper. Brush the tops with more melted butter.

Bake in the preheated oven for 25-30 minutes, or until golden brown and crispy.

Remove from the oven and let cool slightly before serving.