Beef and Potato Piroshki (Пирожки с картошкой)

INGREDIENTS

1 cup

milk (lukewarm)

eggs (set aside 1 yolk for egg wash with 1 teaspoon whipping cream)

3 tbsp

oil - using 15ml measure - melted butter is better

3 1/3 cups

flour

1 tbsp

sugar

1 1/2 tsp

salt

2 tsp

yeast - slightly less than a packet

500 g

lean ground beef

250 g

potatoes (boiled, peeled and mashed)

large onion chopped finely

1/2 tsp

salt (to taste)

1/2 tsp

black pepper