You can print on top of the dish that comes with Foodini, or any other flat surface: another plate, a cake, etc.
In all cases, the Foodini plate/dish should always be in place when printing.
It is important to print on a flat surface.
In the print preview screen, before printing, make sure that you have the correct base height selected. The base height tells Foodini at what height to start printing.

Foodini Dish
The glass dish that comes with Foodini.
Silicon Mat
Default selection. Refers to the Foodini silicone mat. If you use another mat, you may need to adjust the print surface height.
Custom…
If you know the height of your surface, you can enter the number directly. Decimal points are accepted. (For example, a surface height of 10.5.) The maximum height is 110.

If you want to save the height of a custom print surface, tap the star ().
If you do not know the height of your surface, use the Automatic option, described next.
Automatic…
Foodini can help find the height of your custom surface, either automatically as described here, or using the Manual Method. Note that the automatic method may result in a result of +/- 1mm from the actual height – which is fine for most print scenarios.
Put your plate or at least one of your objects (like cookies!) on top of the Foodini dish, making sure at least one item is in the center of the Foodini dish as Foodini will automatically use two laser cross-beams to help measure. These cross-beams meet in the center of the dish.

Shut the door, and tap Automatic… Foodini will automatically put the result in the surface height box.

After Foodini measures the height, you can move the item out of the center of the dish if desired, and add more items (cookies!).