First, make the dough. In a large bowl, whisk together egg, oil and vinegar. Then add in baking powder, salt and pumpkin pie spice. Start adding in flour and kneading until you have a dough that is not sticky but is not falling-apart crumbly. If you add too much flour in, just add a little water. Cover and let rest for at least an hour. Can be refrigerated overnight.
Then make cranberry sauce. In a medium saucepan, combine cranberries, ginger, orange zest, sugar, orange juice and water. Bring to a boil while stirring, and then lower to a simmer. Cook for 15 minutes or until cranberries burst and sauce is thick. Strain through a mesh sieve into a bowl. You can save cranberry pieces and eat them over oatmeal or yogurt. Stir in Dijon mustard (you can use more or less mustard to taste) and place in the refrigerator to cool and thicken slightly.
Now, time to make the knish filling. Wash and peel potatoes and chop into even sized pieces. Add salt, Cover with cold water in a large saucepan and bring to a boil. Simmer for about 15 minutes until potatoes can be easily pierced with a knife. While potatoes are cooking, heat a medium sauté pan over medium heat and add 1 tablespoon oil or schmaltz. Saute the diced onions until soft, about 4-5 minutes. Then add garlic and saute for another minute. Once potatoes are done, drain and immediately mix in remaining oil, remaining salt, onion, pepper and egg yolk and mash with a potato mashed until combined.
Now it’s time to assemble! Preheat oven to 375 degrees F. There are many ways to form a knish, but I like to make mini ones. Roll the dough on a lightly floured surface until 1/8 inch thin. Then cut out using a 3-inch round cookie cutter and remove excess dough. Flatten circles with your palm to form 4-inch circles. Put a tablespoon of filling in each circle and fold up four sides and pinch the corners together. Fold edges over to one side and carefully secure to form a ball. Mix 2 egg yolks with a splash of water and brush all over knishes. Bake for 25 minutes or until golden brown, and serve hot with cranberry Dijon mustard sauce.