Why It Works A blend of cake flour and cornstarch limits gluten development, creating an exceptionally soft, fine-crumbed cake. Using extra egg whites and a butter-oil combination builds a sturdy structure while keeping the cake light, moist, and fluffy. Imitation vanilla and restrained, properly-sized sprinkles recreate the nostalgic flavor and classic confetti look of the boxed cake mix favorite. Few cakes evoke more nostalgia for me than Funfetti—that sprinkle-studded centerpiece of so many childhood birthday parties. It’s not just vanilla cake with sprinkles. It’s that pale yellow crumb with its pillow-soft texture, freckled with perfect dots of color and scented with an almost marshmallowy vanilla aroma that unmistakably signals “birthday.” First introduced by Pillsbury in 1989, Funfetti—a portmanteau of fun and confetti—quickly became a supermarket phenomenon, promising built-in celebration with nothing more than a packet of rainbow confetti candy bits folded into vanilla batter.…