Lisa, I have two 9 inch cakes in the oven now (using the same recipe, omitting brandy though). Never tried it before. I was quite amazed by the quantity of sugar in the recipe, but after tasting the batter
,it seemed quite good. I used so called 'coffee cream' - they sell 15 % fat cream to make milk coffee and it's a good quality one. Nothing like 12 % fat cream here. I think mixing 35% fat whipping cream with milk could be a problem. Was it at the room temperature when you added it to the mixture? If not, I imagine it would cause the mixture to curdle.
Potato, corn and wheat starch are generally used here quite often. It's added to the AP flour to get better, softer cake texture - like making cake flour which is not available here. Wheat starch (Epifin) I've found probably to be the best. I don't use it in the quantities mentioned on the box though - substitute 1/4 to 1/2 of the AP flour - seems too much to me.
If you are interested, I'll let you know how the cakes came out.