Add yeast to ½ cup of hot water (100-110 degrees) and sprinkle 1 teaspoon sugar on top. Don't stir and allow to stand undisturbed for about 10 minutes. If you don't see foam on top and the mixture has not multiplied then stop and get new yeast.Pour yeast and water into bowl of stand mixture.Add butter, milk, egg yolks, and vanilla.Mix until blended and then stop mixer.Add flour, sugar, baking powder, and salt.Mix until dough is well blended and smooth. You may have to scrape off the beater a couple of times to get all the flour incorporated.Once dough is well mixed, switch to dough hook and knead for 5-8 minutes on medium-high speed until dough is smooth and supple and begins to pull away from the bowl. If you don't have a mixer then knead it by hand for about 10 minutes.Remove dough from bowl and place on a lightly floured surface and knead a couple of times, just to make sure it feels right.Turn dough into lightly greased bowl, cover with plastic wrap and allow to rise in a warm place until doubled and puffy, about 2 hours.Mix brown sugar, cinnamon and salt together.Remove half of dough from bowl and place on lightly floured surface.Knead a couple of times to get into a workable dough.Pat and roll dough into a rectangle about 18 x 24 inches.Brush with 1 stick of melted butter, leaving ½ inch bare of the edge nearest you.Sprinkle half the filling generously over dough, leaving the same ½ inch bare.Starting with the long edge furthest away from you, roll dough into a log, finishing with the bare edge.Brush this edge with water and seal to the outside of the log.Measure 1½ inch intervals and cut with a sharp serrated knife or paring knife.Transfer rolls to greased pans, leaving about 1 inch between each roll.Brush the sides and tops of each roll with melted butter.Cover loosely with plastic wrap and set aside in a warm place to rise for 1½-2 hours.At this point you can place the pans in the freezer and freeze. Once frozen, cover the pans tightly with plastic wrap and then aluminum foil.If freezing, I usually mix up the icing and portion into small baggies and freeze along with the rolls. Use ¼ cup plus 1 tablespoon per pan.Remove rolls from freezer the night before and allow to thaw in the refrigerator, then allow to come to room temperature before baking. Or you can remove a couple of hours before baking and thaw on the counter.Bake rolls in preheated 350 oven for 30 to 35 minutes until light golden brown.Remove from oven and allow to cool while you prepare the icing.Mix softened cream cheese, melted butter, milk, vanilla and confectioner's sugar until well blended.Using ¼ cup plus 1 tablespoon per pan, spread icing generously over tops and sides of each cinnamon roll.