Mix the thawed spinach with the crumbled feta cheese. Season the mixture with salt, pepper, nutmeg and chopped garlic. Then pour onto the puff pastry and roll into a strudel. Finally, coat the edges with egg yolk so that the strudel stays closed while baking. Bake in the oven at 180 ° for about 40 minutes. 10 minutes before the end of baking, I spread egg yolks on the strudel so that it turns nice and shiny.