1. Preheat oven to 400°. Combine yeast and warm water in a small bowl; let stand 5 minutes.
2. Meanwhile, whisk together flour and next 4 ingredients in a large bowl; cut cream cheese and cold butter into flour mixture with a pastry blender or fork until crumbly.
3. Combine yeast mixture and buttermilk, and add to flour mixture, stirring just until dry ingredients are moistened. Turn dough out onto a lightly floured surface, and knead lightly 6 to 8 times (about 30 seconds to 1 minute), sprinkling with up to 1/4 cup additional flour as needed to prevent sticking.
4. Roll dough to 3/4-inch thickness. Cut with a 2 1/2-inch round cutter, rerolling scraps once. Arrange biscuits on 2 parchment paper-lined baking sheets.
5. Bake at 400° for 13 to 15 minutes or until golden brown. Brush with melted butter.