Special equipment: a 3-inch biscuit cutter or a 3-inch-wide glass; a pastry blender
For the biscuits: Preheat the oven to 400 degrees F. Grease a baking sheet.
In a large mixing bowl, combine the flour and the chilled, cubed butter. Using a pastry blender, cut the butter into the flour until it resembles a coarse meal. Stir in the baking powder, salt, sugar and baking soda. Form a well in the center of the flour and pour in the buttermilk. Mix with a fork until all of the ingredients are incorporated and the dough begins to shape into a ball. (The dough will be slightly dry.)
Dust a clean work surface with flour, coat your palms, and rub some on a rolling pin. Turn out the dough onto the work surface. Knead the dough for 1 to 2 minutes, folding it over onto itself each time. Roll the dough to about 1/2-inch thick. Dip a 3-inch biscuit cutter or the rim of a 3-inch-wide glass in flour, and then cut out the biscuits. Reshape the leftover dough into a ball, roll it out again, and cut out more biscuits. Repeat this process until the dough is gone.
Place the biscuits on the baking sheet and bake until the tops are golden brown, 10 to 12 minutes. While the biscuits are still hot, brush some of the remaining butter on each biscuit.
For the butter: Stir the butter and molasses together to combine, leaving a few streaks of molasses visible.
Serve the molasses butter with the warm biscuits.
Instead of butter, I like using a non-dairy spread, such as Smart Balance, to make the biscuits; it gives the same texture as shortening.