Baked Sunday Mornings: Purple Velvet Cake (aka Gonzo Cake)

Although I’ve always loved to write, I have to admit that I am embarrassingly lacking in the literature department. My familiarity with Hunter S. Thompson goes as far as watching Fear and Loathing in Las Vegas on a date in 1998 and falling asleep… Not sure what that says about my intellectual depth, the guy I was with, or the film. Anyway, I learned much more about this renegade writer, the proliferator of gonzo journalism, thanks to this week’s recipe for Baked Sunday Mornings. Thompson blurred the lines between objective reporting and personal experience… and there was certainly a healthy dose of acid influencing his work! Baked Occasions delights in celebrating traditional holidays as well as some quirkier affairs, and this Purple Velvet Cake (aka Gonzo Cake), was developed to honor his birthday. True to Thompson’s form, it’s a rather unconventional thing, using an ingredient that one would not normally expect in an American-style cake: ube powder, or dehydrated purple yam. The purpleness is also a nod to Gonzo, the Muppet, so this is just plain fun.

This was not a food item that I ever cooked with, let alone used as a baking ingredient, but BAKED rarely steers us wrong, so I was very intrigued. Ube powder is not necessarily easy to find, depending on where you live; I had always thought it was Japanese (uhhh… for some reason that I cannot explain), so I checked a few Asian markets with no luck. I would have ordered it on Amazon, but a 4-ounce pouch costs a whopping $11-16! After a little more research, I learned that it’s actually a Filipino ingredient, not Japanese. (If I had read the recipe intro a little more thoroughly ahead of time, that is explicitly stated…) Once I knew this, I was able to locate it for about $3 at Western Pacific Filipino Grocery in Sunnyvale, CA, which is fortunately not far from my work. It looks something like dirty purple sand, made up of irregular grains and powder from purple yams, but I knew it would be good because as one of the recipe testers for the book, I’d had the opportunity to test and taste this recipe with Sheri of Pork Cracklins. There are two versions of this cake: this purple velvet one, and an alternate version made with mashed (orange) sweet potatoes; I was tasked with making the latter. It was very cool to taste these very different sweet potato cousins, both of which were delicious. I decided to make the purple one this time, since I did not make it during testing.

The book says to cook the ube powder with water until the reconstituted mixture “looks and feels like mashed potatoes”. In my mind, I was looking for smooth, creamy, and fluffy. In actuality, I let it cook for about 35 minutes (considerably longer than the 5-20 recommended in the book). The granules never really broke down much, so it resembled polenta more than mashed potatoes. I kept wondering if I had done something wrong, but I’m not sure what I could have done wrong, so I finally pulled the pot off the heat, whisked in the canola oil, and let it cool– and it ended up being fine.

The cake batter is made by creaming butter and shortening, adding sugar and vanilla, and then the sifted dry ingredients (all-purpose and cake flours, baking powder, baking soda, and salt) alternating with the ube mash. The granules smoothed out a bit at this point and the batter had a creamy, thick consistency.

The purple color comes from a combination of the ube mash and food coloring. The recipe says to add the color at this point, calling for equal drops of red and blue gel coloring, though I’m not sure why they didn’t just use purple. My red and blue took longer to incorporate evenly into the batter, so I feared that I had overbeaten it by the time the purple was homogenous– it was a grayish-purple, but I didn’t want to add any more. The last step is folding in whipped egg whites, which of course entails even more mixing, so I was fairly uncertain of the success of this cake at that point.

The cakes baked in 32 minutes, a little longer than prescribed, but the centers wouldn’t quite rise all the way. (During the testing process, the baking times were erratic, so I wasn’t super surprised on this.) Sadly, my cakes were a little anemic-looking, barely rising on the edges. Also, the food color molecules were not well-dispersed, which I’d feared– see the pink speckles?

This would simply not do, so I decided to re-bake. This time, I would add the color after the sugar and vanilla, but before the dry ingredients, thus giving it more time to incorporate evenly without extra beating needed. I also added a lot more of it for a deeper purple hue.

While the color was better, sadly, my second batch also did not rise much. The cakes baked in 30 minutes this time.

I think my cake-rising problem was due to poorly-beaten egg whites. The first time, I believe I overbeat them. I’ve never been great at beating egg whites, so I did some research. I knew that egg whites whip up better in a copper bowl, but I think I’ve been underestimating just how much plastic or glass could compromise egg whites’ volume. I didn’t have a copper bowl (just ordered one on Amazon, thank you), so I used a metal one and added ¼ teaspoon cream of tartar to help stabilize them… which didn’t make any difference apparently. This time I think I underbeat them. Or maybe the cake layers just don’t rise much in this recipe?? I was flummoxed, I tell you. *sigh*

But let’s move on to better things: This cream cheese frosting is eyes-rolled-into-the-back-of-your-head delicious. I didn’t have the heart not to add the “optional” vanilla (BECAUSE VANILLA), but it does make the frosting a little brownish. Still, it’s a trade-off I’m willing to make. I used a scant tablespoon, a bit less than what’s written in the recipe. Actually, now that I think about it– the perfect solution is to use vanilla bean seeds, rather than extract. (I’d say ½ – 1 whole vanilla pod?) That way, you retain the whiter color but still have that intoxicating vanilla flavor, plus the pretty vanilla flecks.

The only problem with the frosting is that there isn’t enough of it. It’s the perfect spreading consistency, assuming that you don’t overmix, but there was only enough for a thin layer all the way around the cake, so you can see some of the purple cake showing through. (Since the cakes were already so thin, I didn’t trim the domes off, which means I needed more frosting to fill in the edges between the layers for an overall flat, even cake.) If I’d had more cream cheese in the fridge, I would’ve made another ½ batch. Next time I will make a 1½ batch so that I can make thicker filling layers and have plenty for a thick exterior layer. Believe me, you WILL want ample cream cheese frosting– it’s amazing in and of itself, but it also complements the ube cake so well.

My decoration style was inspired by Sweetapolita, who made this cake back in December. Since my “purple” was more like mauve, I used a purple/pink/green/gold color scheme for the sprinkles. (Incidentally, it looks like her cake layers were also pretty thin on the edges and slightly risen in the centers, so I felt better about my cakes not being super lofty. And really, once assembled, the height on the cake is perfectly fine.) Also, I got this cake stand made a while ago and was waiting for the perfect cake; this was it– a whimsical cake for a whimsical stand!

Regarding color, I would have liked a more blue-purple, so I will err on the side of more blue coloring, remembering that it will turn slightly redder during baking. Sweetapolita used Americolor Regal Purple, which I was conveniently out of, but I would probably try that next time.

The texture of the cake was fantastic– very similar to red velvet, i.e. dense, moist, and tender. The flavor was also somewhat similar, though it has a certain earthy je-ne-sais-quoi from the ube powder. The recipe intro uses that specific word, “earthy”, to describe the flavor, which in name does not sound particularly appetizing, but now I get it. It’s not a bad thing at all, but it’s very hard to describe– you better just make it. 😉

I thought people at work would be wary of this exotic ingredient in a dessert, but they were actually quite intrigued and appreciative that I brought in such an unusual cake. I would absolutely make this again and again, especially for a playful or eccentric occasion. If you’re ready to get your ube on, head over to Baked Sunday Mornings for the Purple Velvet Cake recipe, and check out my fellow bakers’ gorgeous cakes too! No acid trip necessary. 😉

© Dafna Adler & Stellina Sweets, 2015.