Chocolate Frosted Sheet Cake

"The BEST gluten-free chocolate sheet cake with thick swirls of chocolate buttercream and festive sprinkles (of course) • I snuck a bite of chocolate before putting the kids to bed last night, but it turns out I live with a tiny chocolate bloodhound. Zo sniffed and said, “I smell something...I smell CHOCOLATE.” Guess I need to start hiding from the toddler in the pantry to get my chocolate fix (except I don’t have a pantry yet....damn it"