My DD did it a couple of years ago when she was 7. She enjoyed it. They finger-painted aprons and made chocolate chip cupcakes. Her favorite part was passing out the cupcakes to anyone walking by. The passersby were very complimentary of the kids' cooking.
I'm not sure that my DD would have been comfortable doing this at 4 yo, but you know your child. When my DD was 4 and 6, she did the Wonderland Tea Party -- also at GF. Now that she's "almost 10" she says she is too old for all of this stuff.