Usually I've been able to fix a too-dry chocolate cake in one of two ways:
1. Add sour cream to the recipe.
2. Don't overbake. Somebody once told me that all recipes with eggs in them continue to cook after you've taken them out of the oven so if it's fully done in the oven and you take it out it will turn out dryer than you want it to be. Not sure if this is actually true or not but I tend to let it bake like 90-95% and then take it out.
1. Add sour cream to the recipe.
2. Don't overbake. Somebody once told me that all recipes with eggs in them continue to cook after you've taken them out of the oven so if it's fully done in the oven and you take it out it will turn out dryer than you want it to be. Not sure if this is actually true or not but I tend to let it bake like 90-95% and then take it out.