In the bowl of a stand mixer fitted with the paddle attachment, add the flour and mix in the yeast and salt. Add the butter, and mix on low until the mixture gets crumbly. Add the egg, oil, lemon juice, and sour cream and mix until incorporated. Turn the dough out onto a floured surface and mix by hand for five minutes. Alternatively, you can mix with the dough hook for about three minutes (this is what I did). Place the dough into an oiled bowl or container, cover, and refrigerate for 5 to 12 hours. Mix the flour, sugar, walnuts, and cardamom in a medium/large bowl. Stir the vanilla into the melted butter, and pour the mixture over the flour mixture. Stir with a rubber spatula or wooden spoon until the mixture is smooth. It will get crumbly as it cools. This is fine. Preheat the oven to 350 degrees F with a rack in the middle. Line two baking sheets with parchment paper. Divide the dough into 8 equal portions. I used a scale. Cover the dough pieces you are not working with with plastic wrap (I placed the ones I was not working with back in the refrigerator. Working with one piece of dough at a time, roll the dough out between two pieces of parchment paper (I also lightly floured the parchment) into a 10 inch by 6 inch rectangle. Spread 1/8 of the filling over the rectangle, leaving a 1/2 inch border. Fold the border over the filling (see photo above) and, starting with the longer side, roll the dough into a log. Lightly flatten the log with you hands. Using a bench knife, cut the log into 6 pieces and place them on the parchment lined baking sheet. Continue with the rest of the dough pieces. Each baking sheet should hold 24 pastries. Once one baking sheet is filled, brush each pastry with the egg wash and bake them while you assemble the rest of the nazooks on the second baking sheet. Bake, one sheet at a time, for 30 to 35 minutes, until golden brown.