In a small bowl, combine warm water and yeast. Whisk to combine and allow to sit for 10-15 minutes until the mixture becomes foamy.
Meanwhile, combine vinegar and milk in a 2 c. measuring cup. Allow to sit while preparing the remaining ingredients.
In the bowl of a stand mixer, combine flour, sugar, salt, baking soda and baking powder. Using a pastry blender, cut in shortening until it resembles coarse crumbs. Stir in yeast and milk mixture, using the pastry hook mix (knead) until a ball begins to form. Place ball of dough in a large lightly greased bowl. Cover tightly with plastic wrap and place in the refrigerator overnight.
In the morning, prepare filling by combining all ingredients in a medium size bow. Mix to combine.
Remove dough from refrigerator and divide into two equal balls. Roll out one ball on a lightly floured surface. Spread half of the filling over the rectangular slab of dough. Roll up and cut into 12 rolls. Place in a lightly greased 9×13 baking dish. Repeat with the second ball of dough. Cover pans with a dish cloth and set in a draft-free area for 1½ hours or until rolls have doubled in size.
Preheat oven to 375 degrees. Place rolls into oven and bake for 20-25 minutes or until tops are golden brown in color. Remove rolls and place pan on a wire rack to cool for 15 minutes.
Meanwhile, to prepare the frosting, in a saucepan over medium-low heat, combine butter and brown sugar. Heat until the sugars begin to dissolve and bubbles form around the edges (be careful not to burn the sugar). Remove from heat and add in whole milk, salt and vanilla, then the powdered sugar. Spread over warm rolls. Garnish with toasted nuts, serve immediately.