📝 About This Recipe
A true icon of Mid-Atlantic Jewish deli culture, the knish is the ultimate comfort food: a pillowy, savory pastry stuffed with seasoned mashed potatoes and caramelized onions. This recipe captures the magic of the New York street corner classic, featuring a thin, flaky crust and a rich, schmaltz-infused filling that melts in your mouth. Whether enjoyed as a hearty snack or a side dish, these golden bundles of joy represent a beautiful piece of American culinary history.
🥗 Ingredients
For the Dough
- 2 1/2 cups All-purpose flour (plus extra for dusting)
- 1 teaspoon Baking powder
- 1/2 teaspoon Fine sea salt
- 1/2 cup Vegetable oil
- 1/2 cup Warm water
- 1 large Egg (at room temperature)
- 1 teaspoon White vinegar (helps relax the gluten for a thinner crust)
For the Filling
- 2 pounds Russet potatoes (peeled and cut into 1-inch chunks)
- 2 large Yellow onions (finely diced)
- 4 tablespoons Schmaltz (rendered chicken fat) or Butter (schmaltz is traditional for flavor)
- 1 1/2 teaspoons Salt (adjust to taste)
- 1 teaspoon Black pepper (freshly ground)
- 1 Egg yolk (for richness in the filling)
For the Egg Wash
- 1 large Egg (beaten with 1 tablespoon of water)
👨🍳 Instructions
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1
In a large bowl, whisk together the flour, baking powder, and salt. Make a well in the center.
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2
In a separate small bowl, whisk the oil, warm water, egg, and vinegar. Pour this into the flour well and stir until a shaggy dough forms.
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3
Turn the dough onto a lightly floured surface and knead for about 3-5 minutes until smooth and elastic. Wrap in plastic and let it rest at room temperature for at least 30-60 minutes (this is crucial for rolling it thin later).
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4
While the dough rests, place the potatoes in a large pot of salted water. Bring to a boil and cook until fork-tender, about 15-20 minutes.
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5
Meanwhile, melt the schmaltz or butter in a skillet over medium heat. Add the diced onions and cook, stirring frequently, until they are deep golden brown and caramelized (about 15-20 minutes).
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6
Drain the potatoes and mash them thoroughly while hot. Stir in the caramelized onions (and their fat), salt, pepper, and the egg yolk. The mixture should be stiff but smooth. Let it cool completely.
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7
Preheat your oven to 375°F (190°C) and line a large baking sheet with parchment paper.
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8
Divide the rested dough into two equal pieces. On a well-floured surface, roll one piece into a very thin rectangle, approximately 12x10 inches. The dough should be translucent.
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9
Take half of the potato filling and form it into a long log along the bottom edge of the dough, leaving a 1-inch border at the bottom and sides.
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10
Roll the dough up and over the potato log, continuing to roll until you have a long cylinder. Pinch the seam to seal.
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11
Using the side of your hand in a sawing motion (or a dull knife), 'cut' the log into 6 equal pieces. This pinching-cutting method helps seal the ends of each knish.
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12
Stand each piece upright on the baking sheet. Push the top dough edges into the center to partially cover the filling, and flatten the bottom slightly. Repeat with the second half of the dough and filling.
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13
Brush the tops and sides of each knish generously with the egg wash.
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14
Bake for 35-45 minutes, or until the pastry is a deep golden brown and crisp.
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15
Allow to cool for 10 minutes before serving. This allows the filling to set so they don't crumble.
💡 Chef's Tips
Don't skip the dough resting time; it relaxes the gluten so you can roll it paper-thin without it snapping back. For the most authentic flavor, use schmaltz (rendered chicken fat) which provides a savory depth you can't get from butter alone. Ensure your potato filling is completely cooled before rolling; warm filling will steam the dough and make it soggy. If you want a variation, add 1/2 cup of kasha (buckwheat groats) or some sautéed mushrooms to the potato mixture. To get that classic 'deli' look, use the side of your hand to squeeze and divide the dough log rather than a sharp knife.
🍽️ Serving Suggestions
Serve warm with a side of spicy brown deli mustard for the quintessential experience. Pair with a hot bowl of Matzo Ball soup or Borscht for a complete Mid-Atlantic deli meal. These make an excellent side dish for roasted brisket or roast chicken. Enjoy with a cold Dr. Brown’s Cel-Ray soda or a Black Cherry soda. Leftovers can be split in half and seared in a pan with a little butter for a crispy breakfast treat.