Place four cups of Bisquick and two tablespoons of granulated sugar into the bowl of a stand mixer fitted with the paddle attachment.
In a small bowl, dissolve two and one-quarter teaspoons of active yeast and the remaining one tablespoon of granulated sugar into one cup of warm water. Let stand for five minutes or until the mixture becomes frothy.
Add the yeast mixture, one cup of buttermilk, one egg, and one-quarter cup of butter to the dry ingredients. Beat on low until the dough comes together and pulls away from the sides of the bowl. Replace the paddle with a dough hook attachment. Increase the speed to medium and continue beating until the dough becomes elastic-like. Transfer the dough to a large lightly greased covered bowl and let stand for two hours, or until the dough has doubled in size.
Place the dough onto a lightly floured surface. Divide evenly into sixteen pieces and roll each piece into an eight-inch rope and then shape each rope into a spiral. Pinch the end of the spiral to the dough to seal.
Line two baking sheets with parchment paper and place each spiral-shaped roll three inches apart. Cover the rolls with a clean towel and let stand for one hour, or until they have doubled once more in size.
Preheat the oven to 350°F.
Beat the remaining egg in a small bowl and brush over each roll. Bake for fifteen minutes, or until golden.
Melt the remaining two tablespoons of butter in the microwave. Brush the warm rolls evenly and sprinkle with the flaky sea salt.