To make the mushroom filling: In a large skillet, melt the butter over medium heat. Add the onions and cook, stirring occasionally, until they're translucent. Add the ground mushrooms and cook until they release their liquid. Continue cooking until the mixture is dry, then add the sherry, herbs, and Worcestershire sauce., Cook once again until the mixture is dry, then stir in the cream cheese. Taste and season, then remove from the heat and cool completely before using to fill the pastry. This amount is enough to fill about 20 pastries., To make the spinach filling: In a large skillet, heat the olive oil over medium heat. Add the onions and cook until translucent. Add the spinach and bread crumbs, and stir until evenly combined. Remove from the heat and stir in the cheeses and pine nuts; taste and adjust the seasoning, then cool completely before using to fill the pastries. Yield: 3 cups, enough to fill the full batch of pastry dough., To assemble the pastries: Divide the dough into four equal rectangles. Keep the unused portions in the refrigerator. On a floured work surface, roll 1/4 of the dough into a 5" x 13" rectangle. Trim the sides and ends to make straight lines; save these scraps to re-roll for the bottoms., Form the filling of your choice into a rope about 3/4" in diameter. Place the filling down the center of the rectangle. Wet one of the long edges with some water, and roll the other toward it to enclose the filling. Wrap the roll and freeze for 30 to 40 minutes while you roll and fill the rest of the dough., Collect all the scraps and pile them on top of each other. Roll out once more, and cut 4 dozen 1" circles, re-rolling the scraps as necessary. Put the circles on a parchment-lined baking sheet and refrigerate., Take the filled rolls out of the freezer (they should be semi-frozen and firm by now); cut each one into 12 pieces. Take the circles out of the refrigerator and brush with water or a beaten egg. Place each piece of filled dough over a circle, pressing down to seal. At this point you can refrigerate your stovepipes for up to 24 hours, or freeze them and use from the freezer as you need them., To bake: Place as many of the pastries as you need on a parchment-lined baking sheet while you preheat the oven to 400°F. Bake for 15 minutes, until golden brown. Cool for 5 minutes before serving (the filling will be very hot).