Pete’s a Pizza by William Steig

From chapters.ca:
Pete is a normal, healthy boy, but he's decided to become a pizza for awhile. It starts out with Pete's dad kneading the dough - he's really just rolling Pete around on the table - then sprinkling some oil on the dough - the oil is just water - and then adding some tomatoes - really checkers - and then...tickling the dough! Pete's a Pizza is a delightfully irreverent look at the games Pete and his parents play, illustrated in a comic strip format for young readers.