Fry the bacon strips over medium heat in a skillet until crispy. 

Remove the bacon and set it aside. 

Set aside 1 tablespoon (15ml) of the bacon fat. Leave at least 2 tablespoons (30ml) in the skillet and discard the rest. 

Meanwhile, cook the kasha (buckwheat) per package directions to end up with 2 cups of cooked kasha. 

Add the mushrooms and onions to the bacon fat in the skillet over medium high heat and cook for about 10 minutes, or until both are browned. 

Turn the heat down to medium low and add the garlic. 

Chop the bacon into small pieces and add that to the skillet as well. 

Add the dill and cooked kasha and stir everything together well. 

Season with salt and pepper. It should taste slightly over-seasoned. 

Let cool.

Meanwhile, add the sifted flour to a large bowl.

Stir in the salt, baking powder, and cumin. 

In a separate small bowl, beat the egg and egg yolk together with 1 tablespoon (15ml) water and the 1 tablespoon of reserved bacon fat. 

Add the bowl of wet ingredients to the bowl of dried and mix it together with a wooden spoon.

Continue to mix, eventually switching to your hands, forming a ball. If there is still a lot of dry flour, add a dribble of water. If the dough is very wet and sticky, add a pinch of flour. 

Knead the dough ball in the bowl for about 5 minutes, or until it begins to soften. 

Cover the bowl with a damp towel or plastic wrap and let rest for 30 minutes. 

Preheat oven to 375°F (190°C, gas mark 5).

Roll out the dough ball on a floured surface in one big rectangle, about 1/4″ (1/2 cm) thick. 

Lay down the toppings (you may end up with a little extra) in 1 strip on the bottom half of the rectangle. 

Fold the sides over, then roll the bottom edge over the toppings. 

Now roll the top edge back over the bottom edge, towards you. Firm up the log with your hands. 

Cut the log into 6 pieces. 

Take a middle piece and pull it free from the log.

Pinch the dough closed on one side, then flip the piece seam-side down where you pinched the dough closed.

Use your palm to flatten the piece into a thick, flat disk shape, with the open end facing up and in the centre of the disk.

Repeat with the other pieces. The end pieces can just be flipped seam-side down right away. 

Arrange the knishes on a lined baking sheet, being sure that they don’t touch.

Beat an egg in a small bowl, then brush the beaten egg over all of the exposed dough. 

Spoon 1 teaspoon (5ml) of sour cream or yogurt into the centre of each knish. Sprinkle with flaky salt. 

Bake the knishes for 30 minutes or until golden, turning the sheet pan 180° halfway through the cooking time to ensure even cooking. 

Sprinkle with fresh dill, and serve once they’re cool enough to eat. Store these in a ziplock bag or Tupperware container for 2-3 days. They can be re-heated in the oven or microwave. Enjoy!