Hi Sarah! Thanks for visiting us here at the Disney Parks Moms Panel! 
  So happy you stopped by with your question. I too have a sweet tooth and happen to love a macaron. You're definitely on the right track,  
Les Halles Boulangerie-Patisserie at Epcot's World Showcase pavilion in France has a beautiful selection of french pastries and treats, including macarons. I've also been able to enjoy a generously sized macaron during 
Epcot's International Food & Wine Festival. 
 While I have yet to come across a Mickey shaped macaron, I have found that 
Amorette's Patisserie at Disney Springs has a delicious and beautiful variety of sweet french delicacies and more than a few of them are Mickey shaped! They definitely have a variety of flavors of macaron for your 10 year old to enjoy.  
 On a Mom's only trip last spring, I was pleasantly surprised by all of their beautiful offerings. I brought home a mini Mickey mouse shaped cake, Mickey shaped brownie, macaron, and some eclair. Did I mention I have a sweet tooth? All of those treats were happily devoured by myself, my husband and daughters shortly after I arrived home. 
 Hope I was able to give you some good leads!  If you have any other questions, come back to visit us! 
 Veronica