I would like to make an extremely moist chocolate cake either with flour or cake mix. i read 1/4 cup of mayo to batter, extra sugar , butter oil, and even sour cream. which is the best suggestion and proven to give a more moist cake from either scratch or pre-mix. please help. making cake for my daughters birthday. thank you a cooking dad

DESIDERIO:
  Good morning & welcome to our baking forum. Desi, I will not comment on adding any ingredients to a box recipe as I never baked from one before. I feel if you think you can bake a cake from scratch locate a EASY RECIPE & then if you wish post the recipe along with the type of mixer you will use. Also state if you live above 3,000 feet elevation as this will change your recipe somewhat. Adding or subst. a ingredient can be done to make cake moist.
Till then my friend enjoy the rest of the day.

  ~FRESHKID.

Adding extra fat or sugar will make a cake feel “moister” in the mouth. However, you have to be careful if you are modifying a “from-scratch” cake recipe. They can be very sensitive to changes. You might want to start with a cake recipe designed to be very moist. There are some good ones in Shirley Corriher’s “Bakewise.”

Cake mixes are much more forgiving, or so I hear.

Another option for a moist cake is to poke small holes all over with a skewer, and pour on a bit of sugar syrup.

Bungalow Barbara - 16 October 2009 08:08 PM

...However, you have to be careful if you are modifying a “from-scratch” cake recipe. They can be very sensitive to changes. You might want to start with a cake recipe designed to be very moist. There are some good ones in Shirley Corriher’s “Bakewise.”...

Shirley’s Bakewise suggests that butter cakes can be made more moist by substituting up to 10% w/w with cornstarch for flour without significantly changing the structure or texture of the finished cake.  I have tried this with a few pound cake and yellow cake recipe trials and it does make the cake more moist to the mouth, although as the percent cornstarch approaches 10% and higher percentages, the cake becomes more coarse in texture IME.  I haven’t tried it with a genoise or other cake where most of the structure/texture comes from egg foam (where syrup might otherwise be required for moistness/texture improvement).

Has anyone else experimented with this method in egg foam cakes? Just curious…