Heat oven to 400°F. Separate dough into 10 biscuits. Cut each in half crosswise; place on ungreased cookie sheet. With back of spoon, spread 1 tablespoon mustard evenly over tops.
Bake 10 to 14 minutes or until golden brown. Remove from cookie sheet; cool 10 minutes on wire rack.
Meanwhile, in small bowl, mix onions and butter.
Split cooled biscuits. Spread both halves of each biscuit with about 1/2 teaspoon onion mixture. Cut each ham slice into 4 pieces; place on bottom halves of biscuits. Cover with top halves of biscuits.
In small serving bowl, mix dipping sauce ingredients until well blended. Place sauce in center of serving platter; arrange ham-filled biscuits in wreath shape around dip.