The Goldilocks pick: This master chocolatier's mix is just right—not too sweet or too bitter. Plus, you'll love scraping the little nibs of chocolate that never completely dissolve out of the bottom of the mug.

$18 for 18 ounces, Mr. Chocolate

Thick and syrupy, "like a just-melted candy bar," said one of our testers. This mix is so intense—especially when you follow the recipe on the box, which calls for heavy cream as well as milk—that you'll know right away why the suggested serving is less than half a cup.

$25 for 16 ounces, Vosges La Parisienne

Parental guidance suggested: This spicy drink, which includes small amounts of ground ancho chile and nutmeg, will blow away grown-ups. Kids, however, may want to stick to small sips—or to something more G-rated.

$17 for 10 ounces, Mariebelle

Kids especially clamor for this cocoa, which is deliciously milky and smooth (no clumps floating on top) without tasting artificial. As one tester commented, "Tastes like the kind Grandma used to make from scratch."

$7 for 6.25 ounces, Starbucks for store locations

Unlike most cocoas, whose beans are "Dutched" (which results in reduced harshness), this mix is made from fermented beans, resulting in a sophisticated, slightly bittersweet taste—which is good for those who find most cocoas cloying.

$8.50 for 8 ounces, Scharffen Berger

A Silicon Valley priest named Reverend Stan whips up this small-batch brand, which got high marks for its creamy texture (it tastes like it has dissolved marshmallows in it)—even when made with water.

$12 for 12 ounces, Holy Chocolate