Mix 1/2 cup brown sugar with 1 tablespoon cinnamon in a small bowl. Cut biscuits into quarters. Dip each biscuit section into the melted butter, then roll in the cinnamon-sugar mixture.
Place sugared biscuit pieces around the sides of the prepared slow cooker, forming a small wall of dough around the edges. Reserve any leftover butter.
Mix 2 tablespoons flour into the leftover butter. Add 1 tablespoon brown sugar and 1/4 teaspoon cinnamon.
Place blueberries in the center of the ring of biscuit pieces. Pour the butter and sugar mixture over the top of the blueberries.
Cook on Low until blueberries are bubbling and biscuit pieces are golden brown, about 2 hours 45 minutes.