Two drops of gel into a bowl of white frosting and you have the shade of a deep summer sky. A teaspoon of blue spirulina powder into a second bowl and you have the soft, dusty teal of seaglass. Same ...

In a climate like the American South’s, you’d think people would want light, refreshing desserts -- sorbets, maybe. Actually, Southerners are crazy for cake. Crazy-kooky-nutsy, with frosting on it.