Pizza Dough Potato Knishes

For those who have not tasted a real old fashioned knish, these pastry wrapped bundles of mashed potatoes are baked not fried.  This recipe uses plain pizza dough to create a long roll stuffed with the potato filling rather than individual knishes.  It makes excellent buffet fare, cut into individual serving pieces.  And it can be made ahead, even frozen.  (See below for the trick to frozen mashed potatoes that are not watery when defrosted.) 

If you have a lot of dishes to prepare for a holiday buffet, make this mashed potato in pastry ahead and freeze it.  Defrost and reheat it in the oven (microwaving is not recommended to preserve the lovely crust).

Store-bought or homemade pizza dough is a good, pure substitute for the traditional bread dough casing used to make knishes.  Homemade mashed potatoes made with very little milk or broth and seasoned with salt, pepper and chives mimic the classic potato and onion mixture knish lovers admire.  Substituting chives for sauteed onions makes this version a little lighter and faster to prepare.  I use Yukon Gold potatoes which hold up well while the dough wrapping bakes and have a lot pure potato flavor. 

Pizza Dough Potato Knishes
Yield: 2 knish loaves, serves 10-12 people

Ingredients
1 recipe pizza dough (store bought is fine)
8-9 medium potatoes
1/2-2/3 cup milk or broth, warmed
potato flakes*
3 tablespoons butter
1/2 teaspoon salt
1/2 teaspoon dried chives (use 1 tablespoon fresh)
1/4 black pepper

Method

1. Remove pizza dough from refrigerator  and bring to room temperature while making mashed potatoes.
2. Peel potatoes.
3. Place potatoes in a large pot with water.  Water should be at least 2 inches over height of potatoes. Cover, bring to a boil and reduce heat to medium.  Cook potatoes, loosely covered until tender.  This will take 25-40 minutes. 
4. When potatoes are very tender, drain the water and place pot on a heat resistant surface.  Let the potatoes rest, uncovered, a few minutes while some steam (and moisture escapes).  
5. Use a masher to mash potatoes.  You may also use a ricer for this step.  
6. Once potatoes are mashed, add warmed milk or broth in small batches.  Your goal is to have a fairly thick potato mixture.  If you are freezing the knish loaf and using potato flakes, add them at this stage.
7. Stir in butter, salt, pepper and chives. Taste and adjust seasoning to your taste.
8. Preheat the oven to 400˚F.
9. While the potatoes cool a bit, roll out dough.  You will have enough ingredients to make two potato loaves.  
10. Cut dough in half lengthwise and place cooled potatoes down center of each.  
11. Fold the sides up and create a seam.  Use a bit of water to seal the seam.  
12. Seal the edge of the loaves by pinching the dough together and turning under, towards the center seam.  
13. Place knish loaves seam side down on an un-greased baking sheet.  
14. Using a sharp knife, score the loaves just through the dough layer to mark servings.  This will make it easy to slice the loaves into serving sized pieces without pushing out the potatoes.
15. Bake the knish loaves at 400˚F for 15-20 minutes, until dough is completely cooked and browning.  
16. Let rest 10 minutes before slicing.  

Three or more thinner rolls can be made with the same amount of dough and potato filling.  These make great finger food.

*The Trick to Freezing Mashed Potatoes
I've searched online to find out if this trick is generally known and was surprised to find so few references.  I credit Arthur Schwartz for teaching me how to handle freezing mashed potatoes.  (His  fabulous and authentic knish recipe in Jewish Home Cooking is the basis for this faster recipe.) The secret to freezing mashed potatoes is powdered potato flakes.  The flakes absorb excess water from the fresh potatoes and prevent a soggy knish.  Adding potato flakes will also create a mashed potato that will "stand up" a bit more.   For this recipe, add about 1/4 to 1/3 cup potato flakes.  Be sure to look for a pure potato product in the ingredients list on the box, NOT instant mashed potatoes.