The 'Yonah Schimmel' Deli-Style Savory Potato Knish
קנישעס·(kuh-NISH-es)
Chapter 5 — Sides, Sweets & Drinks
A proper knish is a heavy thing. Pioneered on the Lower East Side in 1910, the genuine article features strudel-like pastry wrapped around a dense mound of mashed Russets and caramelized onions. This recipe utilizes a warm-water dough enriched with an egg and a touch of vinegar, making it extensible enough to stretch paper-thin so it crackles when bitten. Forget the deep-fried hockey puck sitting under a street cart heat lamp. Use rendered chicken fat if you can; it's the secret to a knish that tastes exactly like a Saturday afternoon on Houston Street. Pull the bake from the half-sheet pan, add a smear of spicy brown mustard, and respect the gravity of the thing.
Before you start
Whisk the dry and wet dough ingredients separately, then combine.
In the bowl of a stand mixer, whisk together the flour, baking powder, and salt, creating a well in the center. In a separate bowl, whisk the egg, warm water, schmaltz or oil, and vinegar, then pour the wet mixture into the well.
Knead the dough until smooth, then let it rest for at least one hour.
Attach the dough hook and mix on low speed for 4 to 5 minutes until a smooth, slightly oily ball forms. Turn it out, wrap tightly in plastic wrap, and rest at room temperature. Do not skip this rest; the gluten must relax entirely or the dough will tear when stretched.
Boil and dry the potatoes.
Cover the potato chunks with cold water in a large pot, add a generous handful of salt, and simmer for 15 to 20 minutes until tender. Drain thoroughly, then return them to the hot, empty pot off the heat for 2 minutes, shaking gently to evaporate any excess moisture.
Caramelize the onions slowly in schmaltz or oil.
While the potatoes boil, heat the fat in a skillet over medium heat. Sauté the diced onions for 15 to 20 minutes until they are deeply golden, sweet, and jammy.
Mash the potatoes and fold in the aromatics and egg.
Mash the hot potatoes until smooth. Fold in the caramelized onions with all their flavorful pan fat, the kosher salt, pepper, and the beaten egg. Set aside to cool to room temperature; never fill the delicate dough with hot potatoes.
Ingredients
- all-purpose flour2 3/4 cup
- baking powder1 tsp
- kosher salt1 1/2 tsp
- egg1 large
- warm water1/2 cup
- liquid schmaltz or neutral oil1/2 cup
- distilled white vinegar1 tsp
- mixed Russet and Yukon Gold potatoes3 lb
- yellow onions2 large
- schmaltz or neutral oil4 tbsp
- egg1 large
- kosher salt1 tbsp
- black pepper1 tsp
- egg1 large
Method
- 01
Preheat the oven to 375°F (190°C) and divide the rested dough in half.
Line two large baking sheets with parchment paper. Keep one half of the dough covered while you work with the other so it doesn't dry out.
- 02
Stretch the dough until it is nearly translucent.
On a lightly floured surface or over a large sheet of parchment paper, roll the dough into a 12 by 16-inch rectangle. Keep rolling until it is less than 1/8-inch thick; it should look almost like a delicate strudel dough.
- 03
Form a log of potato filling along the bottom edge of the dough.
Take half of the cooled potato filling and form it into a long, thick log, leaving about 2 inches of dough exposed at the very bottom edge and the sides.
- 04
Roll the dough upward, jelly-roll style, to completely encase the filling.
Brush a light coating of egg wash over the exposed top half of the dough. Carefully fold the bottom edge of the dough over the potato log and roll it upward until the filling is fully wrapped in a double layer of thin dough.
- 05
Portion the knishes using the side of your hand or a dull wooden chopstick.
Do not use a knife. Press down gently but firmly onto the log at 2-inch intervals with the floured side of your hand. The blunt pressure will separate the log into individual pieces while simultaneously crimping and sealing the dough over the exposed potato.
- 06
Shape each piece into a plump, round ball.
Take each separated piece and stand it upright, cut side down. Gently press down on the top and pinch the gathered dough together, giving it a slight twist to seal it tightly. Squish it down slightly to form the iconic squat shape.
- 07
Apply the egg wash and bake for 30 to 40 minutes.
Transfer the shaped knishes to the baking sheets, leaving 2 inches of space between them, and brush generously with egg wash. Bake on the middle rack until beautifully golden brown and crisp to the touch, rotating the pans halfway through. Cool on a wire rack for 15 minutes before serving.
Notes
Serve with a proper spicy brown deli mustard.
Do not ruin a perfectly good knish with yellow mustard or Dijon. The sharp, acidic tang of a true NYC-style mustard cuts directly through the rich, heavy starch and fat of the potato filling.
Never reheat leftover knishes in a microwave.
Microwaves will turn this delicate, hand-stretched dough to rubber. Reheat them in a 350°F oven for 10 to 12 minutes to restore the crust's essential crispness.