My mom and I are going to be visiting my sister, her husband, and their 3 year old daughter in Cherry Hill soon.  My niece is the only grandchild not to live near my mom.  My mom has a tradition of baking with all of the grandchildren, and was looking forward to making cookies with my niece , but my brother-in-law has OCD, especially regarding the kitchen, so my sister said it would be best if they did something else together.  My mom is really disappointed and I was just wondering if there were any options in the area for any such activities.  I guess the question would have been enough without the long explanation.  

AAre you asking if there is a shop that you go to where you bake your own cookies? Edited to add, on my phone I didn't see the entire title of your post, which did indeed explain more than the post itself. Sorry, I'm not any help here. Maybe try googling bakeries in that city and call a couple and ask.

Does your sister have a friend with a little girl around the same age as your niece? Maybe you could make it a party and all bake together at the friend's house?

There's a shop in Mullica Hill (south of Cherry Hill) that runs classes for all ages and hosts decorating parties for children.  I'm sure they could accommodate you.