WHILE THE DOUGH IS RISING, MAKE THE GRUYERE SAUCE: In a medium saucepan over medium heat, melt 2 Tbsp of butter. Stir in 2 Tbsp of flour and stir until the flour is cooked out and you have a thick paste. Slowly add in the warm whole milk a little at a time, stirring or whisking until the paste has thinned and you have a thick sauce. Continue to add in the milk a little at a time, stirring as you go. Stir until the sauce begins to thicken. Add in the grated Gruyere, garlic powder, and salt and pepper. Continue to heat and stir until the sauce is thick enough to coat the back of a spoon–if you were to run a finger through the coated spoon, the sauce should not drip into the empty space. Pour the sauce into a small bowl and cover with plastic wrap so that the wrap touches the surface of the cheese sauce–this helps keep a skin from forming. Set aside.