Finding substitutions for wheat flour in baking can be complicated. Simple recipes, such as shortbread cookies, are no problem, because they don't rise and they're supposed to have a light, crumbly texture. Other baked goods, such as bread or cream puffs, rely heavily on wheat flour's gluten. You can substitute coconut flour or other gluten-free alternatives, but the end result won't be quite the same.
About Cream Puffs
Most dessert recipes carefully caution you to keep the ingredients cold, and not to over-mix the dough or batter. Cream puff batter, or choux paste as it's also called, turns that advice on its ear. The batter is made by dumping flour into a pot filled with melted butter and boiling water, then beating it until it comes together in a thick, gluey paste. You beat the batter continuously as it cools, then whisk eggs into it, one at a time. When the stiff batter is piped out in small balls and baked, it inflates into thin spheres of crisp, golden pastry.
The reason for the choux paste's unorthodox mixing technique is simple. Unlike most other pastries, cream puff batter only works if the flour's gluten is well developed. Gluten is made of two proteins, called glutenin and gliadin, which occur in wheat. When they're moistened and kneaded, the two proteins bind together to make the characteristically long, stretchy strands of gluten. When the batter is baked at a high temperature, the moisture in the batter turns to steam. The stretchy gluten proteins and egg proteins in the shell act like a balloon, trapping that steam and helping the puffs earn their name.
It would seem logical that making gluten-free versions of a pastry that relies on gluten is a hopeless endeavor. Fortunately, that's not the case. Coconut flour has no gluten, but you can make passable cream puffs either from all coconut flour or -- more practically -- from a mixture of coconut flour and a grain-based gluten-free flour. In gluten-free cream puffs, the stretchy proteins come entirely from the eggs. To make the batter, follow the same procedure you use for conventional cream puffs. If you're using a recipe intended for coconut flour, make it as directed. If you're using a conventional recipe, add one additional egg white. Bake according to your recipe's directions.
Gluten-free cream puffs made with coconut flour will have a slight coconut flavor, but not enough to take away from their versatility. They will be heavier than conventional cream puffs, and you'll have to slice off a "lid" from the top and scoop out the soft, doughy centers to make a hollow shell. Depending on the recipe, the cream puffs might not have the same deeply golden a color as regular cream puffs. If this happens, brush the tops lightly with a beaten egg before baking them. The egg will bake to a beautiful golden brown.