To find the best grocery-store option, I made Pillsbury's, Ghirardelli's, Duncan Hines', Kodiak Cakes', and Betty Crocker's versions of brownies using box mixes. Here's how each brownie mix ...
Fold in the carrots and then transfer the mixture to the lined tin. Flatten with a spatula and bake for 45–50 minutes, or until a metal skewer inserted in the middle comes out clean. Allow to ...