The intention was pure: My beloved-beloved has a violent reaction to unbaked cows’-milk fat, yet loves cake and chocolate. And a friend — who also loves chocolate — was coming into town. “Ah,” I thought, “let me adapt chocolate icing so that we ALL can eat it.” The idea was to have a rich, dark icing spread onto a store-bought pound cake that had been sliced into layers. The icing would not include cows’-milk fat. The cake was to be purely vehicle for the chocolate.

Here’s what I got: Solid, unspreadable, cake-shredding icing. And it didn’t even taste very good.

Bad Icing from Baking Family

This served me right. I forgot a simple rule of dairy substitution: You can usually reduce the milkfat, but you cannot eliminate it altogether.

I needed a substitute for the normal ingredient — sour cream — so I used Greek yogurt — you know, that really thick, luscious stuff — that was non-fat. This was to be a weeknight-simple company dessert, just melted chocolate chips, the yogurt and a bit of salt and vanillla. I melted the chips in the microwave, then stirred in the yogurt. For one moment it seemed like it would work. But then the icing, instead of staying spreadable, completely seized up.

“Who cares?” said my friend. “Schmear it on the cake anyway.” So I schmeared, and the cake disintegrated, and we laughed.

Icing from Baking Family

The flavor was not what it should have been, either. Fat plays a lovely matchmaking role. A bit of butterfat in the icing would have introduced bittersweet chocolate to tangy yogurt, and they would have danced well. Ginger and Fred. Instead, the two lead flavors were competing against each other like the worst we’ve seen on “Dancing with the Stars.”

So let’s all say it together, and heed this not-so-gentle reminder: When a recipe calls for cream or milk — or even yogurt — you can usually take the fat down, but you can’t take it out.

All photos and recipes copyright 2010 Garside Group LLC