Make the quantity an editable field

If our troop hosts a cook out and wants to know how many hamburgers and hot dogs to purchase, is adding these items in the calendar event details (with a $0 cost) the best way to gather this info? If so, it’d be great if a user didn’t have to click on the add item button, and acknowledge the pop-up between each shopping cart addition. It’d be much faster to have a field where quantity could be set, then added in 1 click.