The endlessly variable, economical, & filling meal

Potato Knish. The first time I had one was from Rein's Deli, CT which was a family pit-stop on long trips between Massachusetts and Virginia, a drive we made frequently. It was my kind of food: potato filling enclosed within a pastry like dough. Starch on starch. You can't go wrong!

Not long after becoming a housewife, I discovered a recipe for knish on Smitten Kitchen. I made it once, and it immediately entered the regular meal rotation. Deb offers one variation of the basic recipe (she does red potatoes with kale, leeks, and cream cheese), but I quickly realized this dish's potential. Like pizza or hot pockets, you can take the basic concept and run with it. Plus, it freezes great as individual portions for days when you need a quick meal or for having a lunch on hand for taking to work.

Potato Knish

Dough ingredients:

2 1/2 cup flour
1 tsp. baking powder
1/2 tsp. salt
1 egg
1/2 cup fat (olive oil, butter, animal fat, or a combination. Rendered chicken fat is traditional, but something I never have on hand)
1/2 cup water
1 tsp. vinegar

Filling ingredients:

1 1/2 lb. potatoes, peeled and quartered
1-2 small onions, chopped
1 tbs. olive oil
1 tbs. butter
Salt & pepper

Directions:

Make dough: Mix dry ingredients together in a medium bowl. In a glass measuring cup, measure water & fat, then add remaining wet ingredients and mix well. Add wet ingredients to dry ingredients and stir until a shaggy mass forms. Turn out onto the counter and knead briefly until dough comes together. Cover with bowl and let rest about an hour.
Cook potatoes: Place potatoes in medium pot and cover with an inch of cold water. Bring to a boil, then reduce heat to medium-high (keep at a low boil). Cook until potatoes are tender, about 20 min. Drain and let cool.
Caramelize onions: While potatoes are cooking, melt olive oil and butter in medium saucepan. Add onions and cook over low heat, stirring occasionally until onions are deeply caramelized. This always takes longer than you think it should.
Make filling: Mix onions with potatoes and mash together. It is fine (and some might argue better) to leave a few lumps. Add salt and freshly ground pepper to taste. (I find you always need more than you think. Just keep tasting until it's right! Nothing is worse than bland potatoes.)
Assemble knish: Preheat oven to 375. Roll out dough into rough 12x24in rectangle. (Deb recommends cutting dough in half and working with 12in squares, but I prefer to get everything done with all at once.) Take potato mixture and shape into a log along the length of the dough. Roll up the potato mixture in the dough. Once rolled, mold little creases into the log where you will make five cuts. Cut on the creases to make six knish. With each piece, pinch the dough together and seal one end (this will be the bottom). Mold piece into a round and on the other end (the top), ease the dough up and around the potato filling to form just a small hole peeking into the filling. Set aside and repeat with remaining pieces. Be patient, sometimes this part can be frustrating.
Bake knish: Transfer shaped knish to pan (or stone) and put into preheated oven. Bake for 45-60 min. Once nicely browned and dough feels crisp, knish are done. Serve immediately, although waiting 15-20min is never a bad idea. The potato filling gets piping hot!

Variations:

Potato & Cheese: Follow basic recipe, but grate in 3oz of cheddar (or other favorite) cheese when mixing the potatoes and onions. Adding has become a given for me.
Sweet Potato, Sausage, & Kale: Roast peeled and cubed sweet potatoes (which helps maintain chunks of potatoes and not so much of mushiness) at 400 until tender. Meanwhile, brown 1/2 lb. ground sausage and saute a bunch of kale with an onion in butter. Mix everything together and season to taste. Use for filling in the recipe.

Notes:

The dough always comes out slightly different for me. It is nevertheless always delicious. Just don't be put off if the consistency changes on you when mixing it together, when you come back to it after the rest, or if it is especially difficult for you when shaping the knish. (Sometimes, it resists being sealed for the bottom seams. Bear with it.)
Fat in the dough: Like with my tortillas, animal fat seems to produce a dough that is fantastic to work with. It also brings depth of flavor to the whole dish. The best alternative I have found is equal parts olive oil and butter.
The original recipe calls for an egg wash. For company, I'll do that. But, for a weekday meal, I'd rather not. I don't mind the rustic look knish have without a wash, though sometimes I will brush them with olive oil for a bit more finish.
Have fun with variations. For the dough, try other vinegars or use broth instead of water. For the filling, use whatever potatoes you have on hand, maybe even sub in some root vegetables. Add flavors and seasonings that sound right. Some garlic with the onions? Delicious. Fresh chives? You bet. The options are endless.
To freeze for later: let the knish cool, wrap in tin foil, and then pop into the freezer. If you remember, pull out the night before using and defrost in the fridge. Otherwise, they reheat well in either the oven or the microwave.