To make the dough, combine flour and salt in a bowl. Use a whisk to combine and remove any flour lumps.
Add butter and using a pastry blender or fork, cut the butter into the flour until it is the size of small peas. Add egg and mix with a spoon.
Add water and mix. Start kneading by hand until the liquid forms into a ball of dough.
Wrap in plastic wrap and chill in refrigerator for 1 hour.
Meanwhile, make the filling.
Heat oil in a skillet. Add onion and garlic and saute until it starts to change color.
Add meat and cook until the meat is browned and cooked through, about 10 minutes.
Add spinach, oregano, cumin, pepper, salt and cilantro. Stir to combine and cook until spinach wilts, about 2 minutes.
Set aside to cool.
Preheat oven to 400 F. Spray a cookie sheet with non stick spray or place a piece of parchment paper on the cookie sheet.
Divide dough in half. Leave the other half refrigerated while you work with the first half.
On a lightly floured board, roll out dough as thin as possible without the dough breaking. Using a 4 1/2" cookie/bisuit cutter, cut out circles. Place about 1 1/2 tablespoons of filling for each circle. Brush the perimeter with milk. Fold over and seal, using the tines of a fork. Place on prepared cookie sheet. Repeat until all the dough has been used.
Brush the tops with milk and bake for 20-25 minutes, until golden brown.