Stir together first 4 ingredients in a large bowl; make a well in center of mixture.
Add buttermilk and next 3 ingredients, and stir just until dry ingredients are moistened. Fold in cranberries. Spoon batter evenly into 12 paper-lined muffin cups, filling two-thirds full.
Bake at 425 for 20 minutes or until lightly browned and a wooden pick inserted in center comes out clean.
Remove muffins from pans to wire racks; let cool 15 minutes.