Preheat oven to 350°. Peel onions, and cut in half lengthwise. Cut each half crosswise into thin slices.
Coat a large nonstick skillet with cooking spray, and place over medium-high heat until hot. Add onions; sauté 8 minutes or until golden. Remove from heat; stir in parsley, poppy seeds, salt, and pepper.
Unroll bread dough, and place on a baking sheet coated with cooking spray; pat into a 16 x 7-inch rectangle. Spread onion mixture over dough, leaving a 1/2-inch border. Bake at 350° for 25 minutes or until golden brown. Remove from pan; let cool 5 minutes on a wire rack.