Make the dough: In a large bowl mix together the flour, baking powder, salt, and sugar then with your hand or a pastry cutter, cut the butter into the flour until it's a rough consistency (you can do this in a food processor if you prefer).

To the flour mixture, add the egg and sour cream then combine until a completely combined soft dough forms then set the dough in the refrigerator for at least 30 minutes, but up to 3 hours.

While the dough is chilling, make your filling: Brown the meat in a skillet then add the onion, carrot, mushroom, and spinach and sauté for ten minutes or until the meat and vegetables are cooked through.

Sprinkle flour over the meat mixture and continue cooking for one more minute then add the water and seasoning and cook another 2-3 minutes until it is no longer wet. Set aside to cool completely.

Once the dough is chilled, divide the dough into 8-12 even pieces. Working one piece at a time, roll the dough out on a lightly floured surface to a thickness of about 1 cm, place a round in the floured dough press then place about 1.5 tablespoons of the filling in the round and close the dough press firmly to seal the edges of the pastry. Continue with the rest of the rounds and filling.

NB: If you do not have a circular dough press simply roll each pastry ball into a circle, fill, and crimp closed with the back of a fork.

Repeat the process until you have used all the dough, place them on a parchment lined baking sheet, poke a few holes in the top of the piroshiki with fork to vent then brush with a beaten egg.

Bake for 20-25 minutes in 190°C degree oven until they are golden brown.