Potato and cheese pierogi with golden butter onions

Mix flour and salt, make a well and add vegetable oil and very warm water (about 120 to 130 degrees); stir to a shaggy dough that pulls away from the bowl.

Turn out and knead a couple of minutes to a smooth, relatively soft ball, adding flour only if too sticky.

Wrap in plastic and rest about an hour on the counter, a few hours in the fridge, or overnight.

Melt a stick of butter over medium heat, add a large finely diced onion and a big pinch of salt, and cook, stirring occasionally, until golden brown; cool and reserve.

Boil three peeled, quartered russet potatoes in salted water until tender, drain well, mash until very smooth and cool to room temperature.

Break up the farmer's cheese with a spoon and season with salt, black pepper and a few shakes of cayenne.

Add two or three heaping spoons of the onions, mostly drained of butter, and mix; add three cups of the cooled mashed potatoes and mix thoroughly.

Roll a quarter of the dough at a time with just enough flour to about an eighth of an inch or thinner; cut circles with a round cutter about three and a half inches across, re-rolling the scraps.

Place about two tablespoons of filling on each circle (let refrigerated filling warm up first); moisten the edge with a little water.

Pinch the centre closed, then press and seal from the centre to each end, pressing out air and flattening the filling; finish by pinching the seam with floured fingers or pleating it.

Alternatively, leave the circle on the counter, set the filling toward one edge, fold over and seal from the centre out.

Boil in salted water 2 to 3 minutes, whether or not they float.

Transfer to a pan of melted butter and cook over medium heat a couple of minutes per side until as golden as desired.

To make ahead, boil, cool and freeze on a plastic-lined plate, bag, and brown from frozen in butter.

Plate, spoon over the golden butter onions and sour cream, and garnish with freshly sliced chives.