We made this pizza using some beige paper, paint and fresh vegetables. The idea of vegetable stamps has been taken from the "Nature Printing" book. Kids have lots of fun with them, and they are much easier to make than rubber stamps.
Cut out a paper circle for the pizza base.
Slice a tomato in half, paint the cut (we used gouache) and pring.
Do the same with a bell pepper.
... and a mushroom.
Experiment with other vegetables and tell me what you got :)