Combine 16 oz buttermilk, 2 ¼ teaspoons dry yeast, ½ oz granulated sugar, 1 ½ teaspoons table salt and 1 large egg in a mixing bowl. Mix on low speed to combine the ingredients. Add ½ of bread flour and mix to combine. Switch to the dough hook if mixing on a stand mixer.
Add the remaining bread flour until the dough gathers on the hook and begins to pull away from the sides of the bowl. Knead on medium for 3 minutes then reduce the speed to low. If mixing by hand stir in as much flour as you can with a wooden spoon, then knead the remaining flour in by hand.
With the mixer running on low, toss in 2 oz butter (softened) a tablespoon at a time. If working by hand, knead in the butter.
Mix on medium for 3 minutes, if the dough is still very sticky add a little flour. The dough will stick to the bottom of the bowl but should gather on the hook. Dump the dough onto a floured surface and knead to form a smooth ball. The dough should be soft and smooth.
Place the dough in an oiled bowl, turning once to coat the surface, cover with plastic wrap. At this point the dough can be refrigerated for up to 2 days or you can proceed with rising. Set the bowl in a warm place until the dough us doubled in size, about 1½ - 2 hours.
Turn the dough out onto a lightly floured surface and roll the dough to form a long log shape. Using a sharp knife or bench scraper cut the dough into 24 even pieces.
Roll each piece of dough under your cupped hand to form a smooth ball. Place the rolls onto a parchment lined baking sheet and brush the tops with melted butter (see note). Set aside in a warm spot to rise until nearly doubled in size and the dough springs back slowly when poked (about 1 hour).
Preheat the oven to 375 °F. Bake the rolls until they are golden brown and feel light when picked up. About 10-15 minutes.
As soon as the roll come out of the oven brush the tops with the melted butter. Enjoy warm or at room temperature.