Spinach and Feta Cheese Puffs Recipe

I have picked out my first recipe to try. I picked something just for the side of the entree due to this being my first. I plan on putting up the recipe a day or two ahead to give anyone who wants to to try it with me and let me know how it goes for you and obviously give me any advice you may have I may need it. So the recipe calls for:

half an onion peeled and minced
2 tbs of butter
4oz of fresh spinach (half a cup) or 3 oz frozen spinach thawed (3/8 cup)
2 tsp freshly grated nutmeg (I am using ground nutmeg)
pepper
two 8-inch squares puff pastry thawed if frozen
3 oz sliced feta cheese (3/8 cup)
1 beaten egg

Melt the butter in a saucepan and saute the onion until softened, about 2 minutes. Add the spinach with plentyy of nutmeg. Cook, stirring until the spinach is soft and the juices have evaporated, 3-4 minutes or 2 minutes if using frozen spinach. Season with pepper and cool slightly

Cut each pastry square in half diagonally. Divide the spinach mixture into 4 portions and place on one half of each triangle. Top with feta cheese. Dampen the edges of the pastry, fold over, and seal well. Brush with beaten egg to glaze.

Place on a baking sheet in a preheated 400 degree oven until cooked through and golden brown, about 15 minutes. Serve immediately.

This meal takes approximately 30 minutes, serves 4 people, and cost me at an estimate of $16.00