I need opinions on the best kind of cocoa powder for baking.
Valhrona has the darkest, nicest smelling cocoa powder I've used, but it's very expensive.
Same goes for Scharffenberger, plus neither is very widely available.
Penzey's I haven't tried, but I hear it's great.
I use Ghiardelli's most of the time because it's pretty cheap but still better than Hershey's (in both smell and color).
Hershey's I use in a pinch to no ill effect.
Nestle's is awful.
Hershey's makes two kinds, regular and "Dutch Process" which reduces the acidity. America's Test Kitchen found the Dutch Process type had a better chocolate flavor, for whatever that may be worth.
Hershey's no longer makes the "European style" that America's Test Kitchen liked. The new Special Dark is awful. Over-alkalized - just black in color - no flavor! We just picked up some Dagoba cocoa powder to try.
I have used a lot of cocoa in the past few years. My preference is for Dutch-processed cocoas, which have a mellow flavor and deep color. The best cocoas I've found are:
Green and Black's (organic,from Whole Foods)
Pernigotti (from Williams-Sonoma or Chefshop)
King Arthur Baker's Catalogue sells a couple of very good brands in large packages that are slightly more economical to use - Bensdorp and Schokinag. Penzey's is another good choice in this category.
Droste is available in most supermarkets. It has become quite expensive, but is definitely an outstanding product.