📝 About This Recipe
A cornerstone of Ashkenazi Jewish soul food, the potato knish is a masterclass in textures, featuring a thin, flaky pastry wrapped around a pillowy, savory mashed potato filling. These handheld treasures are deeply aromatic thanks to onions slowly caramelized in schmaltz or oil, evoking the bustling delis of the Lower East Side and the kitchens of Eastern Europe. Perfectly golden and impossibly satisfying, they represent the heart of kosher comfort cooking.
🥗 Ingredients
The Flaky Dough
- 2 1/2 cups All-purpose flour (plus extra for dusting)
- 1 teaspoon Baking powder
- 1/2 teaspoon Kosher salt
- 1 Large egg (at room temperature)
- 1/2 cup Vegetable oil (neutral flavor like canola or grapeseed)
- 1/2 cup Warm water
- 1 teaspoon White vinegar (helps tenderize the dough)
The Savory Filling
- 2 pounds Russet potatoes (peeled and cubed)
- 2 large Yellow onions (finely diced)
- 4 tablespoons Schmaltz or Vegetable oil (chicken fat (schmaltz) provides traditional flavor)
- 1 1/2 teaspoons Kosher salt (to taste)
- 1/2 teaspoon Freshly ground black pepper (generous amount for a spicy kick)
- 1/2 teaspoon Garlic powder
The Finish
- 1 Large egg (beaten for egg wash)
- 1 teaspoon Water (to mix with egg)
👨🍳 Instructions
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1
In a large bowl, whisk together the flour, baking powder, and salt. Create a well in the center.
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2
In a separate small bowl, whisk the egg, 1/2 cup oil, warm water, and vinegar. Pour this into the flour well.
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3
Stir until a shaggy dough forms, then knead on a lightly floured surface for 3-5 minutes until smooth and elastic. Wrap in plastic and let rest at room temperature for 30-60 minutes.
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4
While the dough rests, place potatoes in a large pot of salted water. Bring to a boil and cook for 15-20 minutes until fork-tender.
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5
In a skillet over medium heat, heat the schmaltz or oil. Add the diced onions and cook slowly for 15-20 minutes, stirring occasionally, until deeply golden brown and caramelized.
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6
Drain the potatoes and mash them thoroughly while still hot. Fold in the caramelized onions (and their oil), salt, pepper, and garlic powder. Taste and adjust seasoning; the filling should be highly flavorful.
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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 portions. Roll one portion out on a floured surface into a very thin rectangle, roughly 10x12 inches.
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9
Place half of the potato filling in a long log shape 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 tightly upward around the potato filling, like a jelly 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 (which seals the edges better than a knife), 'cut' the log into 6 individual knishes.
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12
Stand each knish upright on the baking sheet. Use your thumb to press down the top center slightly to create the classic indent, and tuck the bottom edges under.
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13
Repeat the process with the second half of the dough and filling. Brush the tops and sides of all knishes with the egg wash.
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14
Bake for 35-40 minutes, or until the pastry is a beautiful deep golden brown and crisp.
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15
Let cool for 10 minutes before serving. This allows the filling to set so you don't lose the structural integrity of the knish.
💡 Chef's Tips
Don't skip the dough rest; it relaxes the gluten, allowing you to roll it thin without it snapping back. For the most authentic flavor, use schmaltz (rendered chicken fat) for the onions; it adds a depth that oil can't replicate. Ensure your potatoes are mashed until very smooth; lumps can cause the thin dough to tear during the rolling process. If the dough is too sticky to handle, add flour one tablespoon at a time; if it's too dry, add a teaspoon of water. Knishes freeze beautifully! Flash freeze them on a tray before bagging; bake from frozen at 350°F until heated through.
🍽️ Serving Suggestions
Serve warm with a side of spicy brown deli mustard for a classic kick. Pair with a bowl of hot Matzo Ball soup for the ultimate Ashkenazi comfort meal. Serve alongside crunchy garlic pickles to cut through the richness of the potato. Enjoy as a side dish to a traditional beef brisket with gravy. Accompany with a cold glass of seltzer or a Dr. Brown’s Cel-Ray soda.