Pizza Delivery Shopping Cart - repost

I want to create an online food ordering system with the following capabilities: 1. The Shop should work and seem just like in this site: [login to view URL] 2. Various sizes for pizzas ( small, large, x-large etc.) 3. Possibility to add additional ingredients for specific products. The ingredients should be grouped for specific product groups, such as for pizzas or salads. The cost of the ingredient should be added to the main product. The new cost of the main article must be recalculated as the extras are added (without reloading the whole page). The ingredients must be added / removed by clicking on them. By adding the main product to the basket a window should appear where the possible extras or ingredients are listed and can be added with a click. Also the already added extras can be removed by clicking on them. All the steps from Creation of the shop must me documented.