Here are some more Gluten, Casein and sugar free ideas.

Question: What is shaped like a burger bun and is 10 times more tasty and nutritious for our children?

Answer: A Portabello Mushroom

A tasty addition to a burger instead of using a bun is to use two Portabello mushrooms brushed with olive oil. Put them on the grill, place your burger inside and voila!