I am not a food scientist, so I do not understand the realation of flour to rising agent to liquid, and that is probably my issue. I bake a cake the other day using a recipe I have used many times in the past. The only diffrence this time is I added 1/4 cup Raspberry All Fruit to the mix at the end. I baked 24 cupcakes and 1-6" round cake. The cupcakes baked just fine, but the cake sunk in the middle. What happened?

The recipe I use calls for:
3cups cake four (I use all purpose and subtract 3TBSP)
1TBSP Baking Powder\\
1/2 tsp salt
1 cup butter
2 cups sugar
1/2 cup yogurt
1/2 cup milk
1 1/2 tsp vanilla extract

The cake is baked at 350 ....Can anyone see what could have caused the cake to fall? I would like to try it again, as I got rave reviews on the cupcakes.

How long did you bake it? Did you bake it for the same time you would bake the cake without the fruit? It is possible that the fruit added liquid to the cake, therefore the baking time should have increased. I notice if I open the door to the oven before the minimum baking time I get a sunken center as well. Just an idea.

Baking is a very precise balance. I would venture to say that when you added the fruit the extra liquid is what created the problem. You may want to slightly increase your dry ingredients to accomodate the extra liquid. My general rule of thumb is if I add say some chocolate syrup to a recipe...I leave out an equal amount of liquid. Try a test cupcake...if it falls add a little more dry ingredients...do another test cupcake...if it falls...well you get the general idea. Try to keep track of what you put in so you can make corrections to the recipe for the added fruit.

Thanks everyone. I will try it again, this time without subtracting the extra flour. I'll keep you updated. The cupcakes tasted wonderful, I just need to get them in full size cake form