Preheat oven to 350. Lightly spray mini-muffin pan with canola oil. Chop onions and ham in Food chopper and place in small bowl. Add cheese, egg, parsley, mustard and black pepper; mix well.
Unroll crescent dough and press into one large rectangle. Cut dough into 24 squares. Press one square into muffin pan and and press with mini-tart shaper.
Using small scoop, fill each muffin cup with a scant scoop of ham mixture. Bake 12-14 minutes or until puffs are light golden brown. Remove from pan and serve immediately.