How can I add sour cream to this cake recipe?
If you add too much liquid, (and when sour cream gets warm it does liquefy), your cake batter will be too soupy. But in this case, you’re in! Replace the milk called for in the recipe with the sour cream. I would leave in a 1/4 C. of milk, just to make the batter easy to stir and mix, but other than that…go for it! Have fun.