YUM!! Be sure to flour your board well and grease the cookie sheet. These aren’t very good as leftovers (they wilt in the microwave) but you could freeze them before baking if you wanted to make a big batch.
Melt the butter in a skillet. Add the onion and garlic to the pan and sauté for 3-4 minutes, until the onion is soft and translucent. Preheat oven to 400.
Add the mushrooms, spinach and nutmeg. Cook for 2-3 more minutes.
Stir in the heavy cream, mixing well.
Season with salt and pepper to taste and remove from the heat.
Roll out the pastry on a lightly floured counter and cut in to 4 6-inch rounds.
Spoon ¼ of the filling onto one half of each round and fold the pastry over to encase the filling. Press down to seal the edges of the pastry and brush with the beaten egg. Sprinkle with the poppy seeds. (Freeze at this point if you are doing OAMC.).
Place the packets on a dampened cookie sheet and bake for 20 minutes until cooked through and the pastry has risen and is golden brown.