I spent my day yesterday making an ambrosia cake as part of an experiment for Joseph/Mary's wedding. My goals were to:
- Make sure coconut cupcake recipe can successfully be used to make coconut cake.
- Use cake flour instead of all-purpose flour for said coconut cake (the coconut cupcakes always come out a little dry and cake flour may help with that).
- See if almond flavoring in coconut cake recipe tastes okay with ambrosia cake fillings (orange and pineapple).
- Get a general impression of the flavor of the ambrosia cake.
Here are the brief results of this experiment:
- Cake too moist - use all-purpose flour next time or 2 extra tbsp cake flour per cup of cake flour
- Buttercream too thin - don't melt in microwave
- Pineapple curd too dry - don't overcook. Research pineapple curd.
- Mandarin oranges were slightly metallic - rinse under water first? Look for mandarin oranges canned in glass jars?
Still interested? Read on!
I got the fillings for this recipe at cooksillustrated.com under "Ambrosia Cake." However, the people at Cook's Illustrated suggested torting an angel food cake into four layers, then filling with orange buttercream and mandarin oranges, pineapple curd, then orange buttercream and mandarin oranges again (see figure).

Angel food cake doesn't seem like it would work for a wedding cake. Angel food cakes have to be baked in a pan with a low surface area because the cake clings to the side of the pan for support while it's baking. Therefore, it's usually made with a tube pan and sometimes a loaf pan because they are small enough in area for the cake to rise successfully. And I can't use a tube pan or loaf pan because they wouldn't match the other tiers of the wedding cake.
So I decided to try my coconut cupcake recipe, which I think I found in Good Housekeeping, and just use it as a cake recipe. I mean, the way to make cupcakes is to use regular cake batter baked in cupcake tins, so why not the opposite? However, I made the mistake of using cake flour when baking the cake where the recipe calls for all-purpose flour. According to joyofbaking.com, when replacing all-purpose flour with cake flour, the ratio of all purpose flour to cake flour should be 1 C = 1 C + 2 tbsp. Yesterday the thought came to my mind to look up this conversion, but I didn't act on it. So the cake came out way too moist. Also, cupcakes are smaller than a 9" cake, so of course it's easier for them to dry out while baking. Therefore, I could have used the all-purpose flour for the cake and it might not have dried out.
I also messed up my buttercream. I had leftover buttercream icing from
cake results #1, so I let it sit out on the counter to come to room temp... and it sat, and sat, and sat.. but it was taking forever in my 60 degree apartment, so I popped it into the microwave for 30 seconds (it was about 2 cups of icing). Well, 30 seconds later the whole thing was a puddle, so I had to stick it in the freezer and hope for the best. Even after it cooled, I was too lazy to bust out my hand mixer so I beat it by hand, hoping it would thicken on its own, and it did, but not enough. So the orange buttercream layer was a little watery and soaked right into the ultra-moist cake.
The canned mandarin oranges didn't exactly float my boat, either. I could've sworn I tasted a metallic flavor in them last night, but today when I sampled the cake again it was gone. So I guess that's okay.
Plus I screwed up the pineapple curd. You boil some pineapple juice, add it to a mixture of 2 eggs, 1 egg yolk, and 1/2 C of sugar, stir it, then heat it up some more. It's supposed to heat up to a point where it sticks to the spoon, but for me that never happened, so I just kept stirring it until I got sick of it. And then, when I finished it and put it on the cake, it was too thick. What the heck? I'll have to try that one again and maybe do some research on making curd.
So yeah, the cake was too moist, the buttercream was too watery, and the curd was too dry. Plus I ran out of cream cheese frosting so the cake doesn't look as beautiful as it should. But it's just an experiment. Here's a photo:

I tried to redeem it in the looks department by putting this pineapple/orange design on top. :)

Too messy!

However, I will say that the combination of coconut cake plus pineapple and orange was delicious. And the almond flavoring didn't clash with the other flavors of the cake, so I will keep it.
So the next time I make this cake (next week? later this week?) I will be sure to use all-purpose flour and take more care with the orange buttercream and pineapple curd. And I will rinse off the mandarin oranges to avoid a metallic flavor.