Well, here we are, trying a third time.
I allowed the cold ingredients to warm for 2-3 hours.
Using a hand mixer on low speed, I creamed the butter with the sugar first.
I added the eggs slowly.
Mixing by hand with a wooden spoon, I alternated sour cream, milk and flour.
I added the cranberries.
The batter looks really thick, just like before. It doesn't flatten out when poured, the way store bought mixes do. Still, it feels a little lighter.
I put two pans in the oven, instead of three.
I may cook it longer than the recommended 40 minutes, because that might be for just one pan?
It would be nice if this worked for Christmas dinner.