In a stand mixer fitted with the dough hook, mix the yeast with the water and 1 teaspoon of the sugar. Let stand until foamy, 10 minutes. Beat in the remaining sugar, 3/4 cup of the butter and the milk, eggs and kosher salt. At low speed, stir in the 7 1/2 cups of flour until the dough comes together; add more flour by the tablespoon, if necessary. Mix at medium speed until the dough forms a loose ball around the hook, 3 minutes. Brush a large bowl with some of the melted butter. Transfer the dough to the bowl and cover with plastic wrap. Let stand in a warm spot until doubled in bulk, 1 1/2 hours.