Sprinkle your yeast over your water in a small bowl. Set aside and allow to sit for at least 5 minutes.
Combine the milk, sugar, butter, salt, and egg in the bowl of an electric mixer. Stir to combine. Add 2 cups of flour and stir until fully incorporated. Stir in the yeast mixture. Add the remaining flour and knead 5-10 minutes or until smooth.
Transfer your dough to a greased bowl. Cover with a clean towel and allow to rise until doubled in size (1-2 hours).
Turn your dough out onto a lightly floured surface. Roll into a 15x9 inch rectangle. Spread 1/2 cup soft butter across the dough. Whisk together the brown sugar, salt, and cinnamon. Sprinkle over your butter. Roll, starting on the long end, to form a large log. Cut into 15 pieces.
Place your rolls into a lightly greased 9x13 pan. Cover with plastic wrap and place in the refrigerator overnight.
In the morning place the cinnamon rolls in the oven without turning it on. Let them come to room temperature and slightly rise for 45 minutes to 1 hour. Remove from the oven and preheat to 350 degrees.
Bake 25 minutes or until slightly browned.
Whisk together the frosting ingredients and spread over the top. Serve along side your favorite breakfast recipes.