Make the Dough: In a large measuring cup, whisk the buttermilk, melted butter, eggs, and vanilla bean paste together until combined. In a large bowl, whisk 4 cups all-purpose flour, sugar, yeast, and salt together. Make a well in the center of the bowl and pour the buttermilk mixture in the center. Spoon the flour with a wooden spoon into the center until the flour is moistened and has a shaggy look to it. Turn the dough onto a lightly floured surface. Pour the remaining 1/4 cup of flour next to the ball of shaggy dough. Knead the dough, dusting your hands periodically with the flour until the dough is smooth and elastic, about 10-12 minutes. The dough should be tacky to the touch, but not sticky. Place the dough in a lightly buttered bowl and wrap the bowl tightly with plastic wrap. Let the dough rise in a warm, draft-free place until the dough doubles in size, about 2 to 2 1/2 hours.  Fill the rolls: Liberally grease a 9x13 inch baking pan or Pyrex dish. Sprinkle the pan lightly with granulated sugar and set aside. In a small bowl, mix the granulated sugar, ground cinnamon, and salt. Turn the dough onto a lightly floured surface and press or roll the dough into a 12x16 inch rectangle. Brush the butter evenly over the dough. Sprinkle the cinnamon/sugar mixture, leaving a small 3/4 inch border along the perimeter of the dough. Press on the filling to help it adhere to the dough. Loosen the dough from the counter using a bench scraper (or metal spatula), and from the long end, roll the dough very tightly into a long cylinder. Pinch the seam closed and roll the log seam side down. Slice the cylinder into 12 evenly sized rolls (about 1½ inches wide) using a serrated knife. Arrange the rolls cut-side down in the prepared baking pan and wrap with plastic wrap. Let rolls rise in a warm place until the rolls have doubled in size, about 1 to 1½ hours. The rolls will press into one another. While the rolls rise, preheat the oven to 350° Fahrenheit. Adjust the oven rack to the middle position. When rolls have risen sufficiently, remove plastic wrap and place in the oven. Bake the rolls until golden, about 25 to 30 minutes. Remove rolls from the oven and allow to cool slightly before pouring the pecan caramel. Make the pecan caramel: Melt the butter in a medium-sized saucepan over medium heat. Add the brown sugar and whisk until combined. At first, it will seem as if the mixture will not come together. Keep whisking. Allow to cook, whisking constantly for 3-4 minutes. Reduce the heat to low and add the salt, vanilla extract. Add the heavy cream slowly in a stream. Be careful. The mixture will bubble. Raise the heat to medium and cook, whisking constantly for about 3-4 more minutes. Reduce the heat to very low and allow the mixture to thicken slightly another 2 minutes. Add the chopped pecans and pour immediately over warm rolls.