Potato Knishes

DOUGH RECIPE

4 cups unbleached all purpose flour, plus more for rolling out the dough

1 teaspoon baking powder

1 teaspoon kosher salt

1/2 teaspoon granulated onion

1/2 teaspoon granulated garlic

1 large egg

1/2 cup buttermilk

1/2 cup vegetable oil

FILLING RECIPE

2 pounds russet potatoes (about 2 large potatoes)

4 tablespoons (1/2 stick) salted butter

1 small yellow onion, halved and thinly sliced

3 large garlic cloves, miced

1/2 cup buttermilk

1 1/2 teaspoons kosher salt

1/2 teaspoon ground black pepper

2 eggs, lightly whisked

FOR SERVING

Sour cream

1 bunch green onions, thinly sliced

Spicy brown mustard

DIRECTIONS

To make the dough, pulse 3 cups of the flour, baking powder, salt, granulated onion, and granulated garlic in a food processor until combined. Turn off the machine and add the egg, buttermilk, and oil. Pulse the ingredients together until completely combined and then, with the motor running, stream in 1/4 cup cold water until the dough forms a ball. Remove the dough, wrap it tightly in plastic wrap, and refrigerate it at least 1 hour before using.

Place a rack in the center of the oven and preheat the oven to 375 degrees. Line two baking sheets with parchment paper. Place the potatoes in a medium saucepan and cover them with cold water. Bring the water to a boil, then reduce the heat and simmer for about 1 hour , until knife tender. drain the potatoes and set them aside to cool slightly.

While the potatoes are cooking, melt the butter in a medium sauté pan over medium heat. Add the onion slices and cook until lightly caramelized, about 25 minutes stirring occasionally so they don’t burn. Reduce the heat to low, add the garlic, and cook about 5 minutes, until the garlic is soft and the onion slices are evenly caramelized. Set aside to cool completely.

Peel the potatoes and place them in the food processor. Add the buttermilk, salt, and pepper and pulse until the mixture is just smooth; do not overmix or the mixture will become gummy. Remove the mixture from the food processor to a medium bowl, stir in the caramelized onions, and set filling aside.

Remove the dough from the fridge. It will feel a bit oily; this is normal. Generously dust a clean work surface and your hands with flour and cut the dough in half. Roll the dough into 12x16 inch rectangle. Cut the dough width-wise into three 4 inch strips, and then cut the strips in half crosswise. This will give you six 4x8 inch rectangles. Repeat with the second half of the dough.

Place 3 tablespoons of the filling in the center of a dough rectangle and brush the edges of the dough with egg yolk. Fold the dough over the filling to make a 4x4 inch square, then firmly press the edges of the knish together to seal completely, taking care to push out any excess air from the filling. Poke a small hole on top of the knish to create a vent, then set 6 knishes on each lined baking sheet. Form the remaining knishes, then brush the tops of all the knishes with more egg wash.

Bake until lightly golden brown, about 20 minutes. Set aside to cool for about 10 minutes before serving.

Serve the knishes with sour cream, green onions, and spicy brown mustard.