Preheat oven to 350 degrees F . Lightly coat four 6-ounce ramekins or custard cups with nonstick cooking spray. Place ramekins in a 2-quart square baking dish; set aside. In a medium bowl, stir together pumpkin, milk, 1/3 cup brown sugar, egg whites, and pumpkin pie spice. Divide pumpkin mixture among ramekins.

In a small bowl, stir together oats, 1 tablespoon pumpkin seeds, 2 teaspoons brown sugar, and butter with a fork until crumbly. Sprinkle oat mixture evenly over pumpkin mixture.

Place baking dish on oven rack. Pour boiling water into the baking dish around ramekins to a depth of 1 inch. Bake for 40 to 45 minutes or until a knife inserted near the center of each pudding comes out clean. Carefully remove ramekins from water. Cool on a wire rack at least 15 minutes before serving. Or after cooling up to 1 hour, cover and chill up to 24 hours. If desired, sprinkle with additional pumpkin seeds before serving.