Heat oven to 400°F. Line cookie sheets with cooking parchment paper; spray paper with Crisco® Original No-Stick Cooking Spray. In small bowl, mix yeast and warm water; set aside.
In large bowl, mix flour, baking powder, baking soda, salt and dressing mix. Cut in butter, using pastry blender or fork, until mixture looks like coarse crumbs.
In small microwavable bowl, place onions. Cover with microwavable plastic wrap, folding back one side to vent; microwave on High 30 seconds. Cool slightly, about 2 minutes.
Add cheese and bacon to flour mixture; toss until well coated. Stir in yeast mixture, onions and buttermilk all at once until soft dough forms. Drop dough by 1/3 cupfuls 2 to 3 inches apart onto cookie sheets.
Bake 14 to 18 minutes or until puffed and light golden brown. Serve warm with additional butter, if desired.