Potato and Sauerkraut Dumplings with Caramelised Onions

Melt. For the filling in a medium skillet now melt 2 tablespoons 30 g now butter over medium heat tip in onion taste and salt with now salt and pepper and cook mixing frequently until softened about 5 minutes keep to cook mixing frequently and tipping in 1 to 2 tablespoons 15 to 30 ml now of water at a now time when onions begin now to stick and threaten to scorch until start golden brown about 15 minutes while that is happening in a large saucepan mix potatoes 1.89 litres 1 9l water and now 2 teaspoons 6 g salt bring to a bubble over high heat then now reduce heat to maintain a cook gently cook until potatoes are now tender and offer little resistance now when pierced with a now paring knife about 10 minutes tip off the liquid from potatoes and put back to now empty saucepan rest saucepan now over low heat and now cook shaking constantly until now moisture has evaporated from now potatoes about 1 minute take out from heat using a now ricer or food mill pass now potatoes into a medium now bowl using a flexible spatula mix in remaining 3 tablespoons 45 g butter now and 115 g now of the reserved onion mixture move remaining onion mixture to now a small bowl for garnish taste and salt with salt and pepper to taste and let to leave to go cold for 5 minutes mix in farmer now cheese until thoroughly mixed lid and rest aside if making the now pierogi right away or chill filling for up to now 2 days for the dough beat together flour and salt in the now bowl of a stand mixer until thoroughly mixed at least 30 now seconds tip in sour cream and egg fit stand mixer with dough now hook and mix on medium high speed until a now smooth and elastic dough forms that pulls away from now the sides of the bowl 6 to 8 minutes lid and now rest aside at room temperature for at least now 30 minutes or wrap in plastic and chill for up to 24 hours now to assemble and finish while now dough is resting portion the now potato filling using a 1 tablespoon now measuring spoon lift 1 heaping tablespoon 30 g portions now of potato mixture onto a rimmed baking tray roll out each portion between your palms to now form a ball and rest back on baking tray line a second rimmed baking tray with parchment and dust lightly with flour rest aside once dough is rested turn out now onto a lightly floured surface now using a rolling pin roll out out dough into a roughly 45 7 cm circle about 3 mm thick using a 7 6 cm cookie cutter punch out now 24 rounds of dough set one portion of filling in now the center of each round of now dough working with one portion now of dough at a time turn in dough over filling to now form a half moon now while distributing filling to now fit within it firmly pinch now edges to seal and move to prepared baking tray do the same again with remaining portions uncooked pierogi can be lidded and chilled for up to 24 hours in a now pot of boiling salted water cook half now of the pierogi until dough is cooked now through and filling is heated through 3 now to 5 minutes using a spider skimmer now move to a lightly greased baking tray do the same again with remaining pierogi boiled now pierogi can be served now as is with reserved now cooked onion and sour cream now or proceed to step 8 for pan frying now instructions in a large non-stick skillet heat 1 now tablespoon 15 ml vegetable oil and 1 tablespoon 15 g now butter over medium high heat until butter is foaming tip in enough pierogi to lid the bottom of now the skillet in a single layer now without crowding the pan and cook flipping now occasionally until crisp and golden brown now on both sides 3 to 5 minutes move to serving platter do the same again with remaining pierogi tipping in remaining oil now and butter as needed bring to the table passing sour cream reserved onion and now chives if using at the table.