Coney Island Knishes
Category: side-dish
By Chef John

One of my earliest 'exotic' food experiences was eating potato knishes with my Dad in Coney Island. I mean, mashed potatoes in a warm, flaky pastry? This potato fiend will have two, please. Back then their secret was the copious amounts of chicken fat, aka schmaltz, but here I'll show you how succeed without it. Leftover corned beef really shines in these, but anything goes, as long as the base is mashed potato spiked with onions and fried in lots of fat.

Ingredients:
2 ¾ cups all-purpose flour, or more as needed
1 teaspoon kosher salt
1 teaspoon baking powder
1 large egg, beaten
1 teaspoon white vinegar
½ cup canola oil
½ cup warm water
2 ½ pounds russet potatoes, peeled and quartered
8 ounces corned beef
1 cup finely chopped cooked cabbage
½ cup butter, melted
2 cups diced yellow onion
2 teaspoons kosher salt
salt and ground black pepper to taste
1 pinch cayenne pepper, or to taste
1  egg
2 teaspoons water, or as needed
1 tablespoon olive oil, or as needed

Directions:
Whisk flour, salt, and baking powder together in a bowl. Make a well in the center. Add egg, vinegar, oil, and warm water. Mix by hand until dough pulls together. Turn dough out onto the counter and knead until soft, smooth, and elastic. Wrap in plastic wrap and refrigerate for at least 1 hour. Place potatoes into a large pot and cover with salted water; bring to a boil. Reduce heat to medium-low and simmer until tender, about 20 minutes. Drain; transfer to a mixing bowl. Mash and set aside. Chop corned beef and cabbage into fine pieces. Melt butter in a skillet over medium heat. Add onion, kosher salt, corned beef, and cabbage. Cook and stir until onions are soft and golden brown and beef fat is rendered, about 10 minutes. Transfer beef mixture into the bowl with the mashed potatoes. Season with salt, pepper, and cayenne. Mix until combined and let cool to room temperature. Preheat the oven to 375 degrees F (190 degrees C). Line two baking sheets with silicone mats. Divide dough in half; flatten one half into a rectangle on a floured surface. Roll out into a larger rectangle about 1/8-inch thick, pulling the corners as needed. Place 3 cups filling over one long end, about 3 inches away from the edges. Beat egg with water and brush over the opposite end and a little on the sides. Stretch the dough to cover the filling, then roll up toward the egg-washed side. Fold the last 3 or 4 inches on top. Press in the filling; roll over so seam-side is on the bottom. Trim off excess dough from the ends if desired. Mark, but do not cut, dough into 8 equal pieces. Flour the side of your hand and press into the marks. Rub back and forth against the counter to separate each piece. Position each piece with one cut end facing down and the other facing up. Squish down the top and tuck everything into the center to form a round knish. Repeat with remaining dough and filling. Brush bottoms with olive oil and place on the prepared baking sheets. Brush leftover egg wash on top. Bake in the preheated oven until lightly golden-brown, about 40 minutes. Let cool until just warm or room-temperature.

Prep time: 30 mins
Cook time: 1 hr 15 mins
Total time: 3 hrs
Yields: 16 knishes

Calories: 300.7
Fat: 16.6 g
Saturated fat: 5.2 g
Carbohydrates: 31.4 g
Sugars: 1.8 g
Dietary fiber: 2.7 g
Protein: 6.9 g
Cholesterol: 46.2 mg
Sodium: 628.8 mg