For son Cree Hardrict's first birthday celebration, Tia Mowry knew the perfect theme. "Elmo has been Cree's traveling buddy since he was born. Elmo has kept Cree entertained around the globe!" the actress tells PEOPLE. The Sesame Street star was the hit of the party, tickling the top of a spectacularly cute gluten-free vanilla cake with chocolate chocolate-chip filling, made by Cake Divas.