Polish Potato Dumplings (Kopytka) with Mushroom Sauce

INGREDIENTS

For the dumplings:

500 g

potatoes (peeled)

80 g

flour

salt and pepper

For the mushroom sauce:

300 g

mushrooms (finely chopped)

2 tbsp

olive oil (plus more for serving)

2 tbsp

thick yogurt

and 1/2 teaspoon flour

2 tbsp

water

salt and pepper

Chives for garnish