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potato and onion knish with caraway seeds
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Potato and Onion Knish

These potato and onion knish are filled with creamy mashed potatoes, caraway seeds, and caramelized onions, then wrapped in a homemade buttery and flaky pastry crust.
Course Appetizer, Dinner, Lunch, Side Dish
Cuisine American, Jewish
Cook Time 2 hours
Servings 8 knish

Ingredients

MASHED POTATOES INGREDIENTS

  • 1.5 lb Yukon gold potatoes, peeled and quartered
  • Low sodium chicken broth, enough to cover the potatoes by an inch
  • 1 tbsp unsalted butter
  • 3/4 tsp salt, or to taste
  • 1/4 tsp ground black pepper, or to taste
  • 1/4 cup whole milk
  • 1/2 tsp caraway seeds, plus more for sprinkling (optional)

CARAMELIZED ONIONS INGREDIENTS

  • 2 large onions, peeled and very thinly sliced
  • 3 tbsp extra-virgin olive oil
  • 1/4 tsp salt, or to taste
  • 1/4 tsp ground black pepper, or to taste

KNISH PASTRY DOUGH INGREDIENTS

  • 2 cups all-purpose flour 
  • 1/2 tsp baking powder
  • 1 tsp kosher salt
  • 1 cup unsalted butter
  • 2-4 tbsp low sodium chicken broth, COLD
  • 1 egg beaten with some water (for washing)

Instructions

CARAMELIZED ONIONS COOKING INSTRUCTIONS

  • Start making the caramelized onions first, since they will take the longest.
  • Peel and thinly slice onions.
  • Add the olive oil to a large skillet set over medium heat. Once oil is hot, carefully add all the onions to the skillet and stir to coat with the olive oil.
  • Cook onions over medium heat for 45-60 minutes, or until soft and golden brown, stirring regularly every 5 minutes to ensure no onions start burning.
  • Remove caramelized onions from heat and season with salt and pepper to taste. Set aside.

KNISH PASTRY DOUGH INSTRUCTIONS

  • While the onions caramelize, make the pastry dough.
  • Slice butter into thin pats. Set aside.
  • Cut a piece of plastic wrap and place it aside.
  • Whisk together the flour, baking powder, and salt in a medium bowl.
  • Add the sliced butter to the bowl, then massage the butter into the flour, breaking up the pats with your fingers into smaller pieces. However, leave some larger pieces of butter in the mixture, as they will create tenderness later. After 3-4 minutes, you should have a crumbly dough mixture.
  • Add the chicken broth to the flour mixture, one tablespoon at a time. Work the broth into the flour mixture by tossing it with your fingers to make sure all ingredients are moistened.
  • You don’t want the dough to become entirely homogenous. You should be able to take a handful of dough crumbles into your hand, squeeze, and have the dough stay together – this means the dough is moist enough and you can stop adding broth.
  • Put the remaining chicken broth back in the fridge to stay cold—you may need it later when you roll out the dough.
  • Scoop the dough onto the plastic wrap and squeeze it together into a flat disc. Wrap the disc in the plastic wrap and refrigerate for 30-60 minutes.  

MASHED POTATOES COOKING INSTRUCTIONS

  • After putting your pastry dough in the fridge, and while the onions are still caramelizing, make the mashed potatoes.
  • Peel and cut your potatoes, then place them in a medium pot.
  • Fill the pot with chicken broth, enough so that the potatoes are completely covered by at least an inch of broth.
  • Boil the potatoes over medium-high heat until fork tender.
  • Drain the cooked potatoes, then add them back to the pot or place in a large bowl for mashing.
  • Add the butter, milk, salt, pepper, and caraway seeds (if using) to the potatoes, then mash all together to your desired consistency. (I like my potatoes thick and smooth.)
  • Set mashed potatoes aside and let cool. 

KNISH FILLING INSTRUCTIONS

  • Preheat the oven to 375F.
  • Line a baking sheet with parchment paper and set aside.
  • Stir the caramelized onions into the mashed potatoes until completely combined. Set aside. If the filling is still hot, let cool to room temperature.
  • Roll out the pastry dough on a well-floured surface until the dough is roughly 11x15 in size and about 1/8 inch thick. If the dough keeps crumbling, work a little more of the reserved cold chicken broth into the dough and re-roll.
  • Use a sharp knife to cut away the rough edges of the dough to create a perfect rectangle. Set the dough scraps aside to use later.
  • Scoop the room temperature mashed potato and onion filling in a row across the length of the dough, leaving about1 inch from the pastry’s edge. (See photo above.)  
  • Fold the top flap of dough over the filling so you have a little log. (See photo above.)
  • Roll up the remaining dough over the filling, then place the log seam-side-down on your work surface. (See photo above.)

KNISH SHAPING INSTRUCTIONS

  • Trim the ends off the log; discard the potato-filled dough scraps.
  • Divide the log into 8 equal(ish) pieces using a sharp knife. (See photo above.)
  • Take one piece and place it in the palm of your hand so that the open sides are now the top and bottom of your knish. Gently pull the edges of the openings and gather them together to seal off the opening. Some filling might squish out, and that’s okay.
  • If there isn’t enough dough to cover both openings, take a reserved scrap of dough and fold it around the BOTTOM of the knish. You want the bottom to be sealed, but the top of the knish can remain a bit “open” with some filling peeking out.
  • Repeat the shaping process with the remaining seven pieces until you have eight round knish.

KNISH BAKINGINSTRUCTIONS

  • Whisk together the egg and a few drops of water in a small bowl to create an egg wash.
  • Place the round knish on the baking sheet a few inches apart; they will poof up in the oven.
  • Brush each knish with the egg wash. Sprinkle tops of knish with caraway seeds, if desired.
  • Bake the potato and onion knish at 375F for 20-30 minutes, or until the knish are golden brown.
  • Remove knish from the oven and let cool on baking sheets or wire rack. Serve warm.