A combination of factors led to these cupcakes.
1. After making that raspberry buttercream, but knowing I could make it better, I was obsessed with creating a new berry buttercream, and the bag of organic blackberries in my freezer that I had purchased on sale for smoothies were just sitting there waiting for me.
2. I love lime. Always and forever.
3. Perhaps most importantly, I just watched 5 episodes of DC Cupcakes, a TLC program that showcases a cupcake shop in the capital. I find the scripted banter, escapades, and arguments particularly annoying on this show, but I sat through it for the cupcakes. As cupcakes go, these seem decent to me. I like that the frosting is standardized and the decoration minimal; these are signs that flavor is what matters to this bakery. And, inevitably, after watching hundreds of dozens of beautiful cupcakes being baked, decorated, sold, and shipped, I couldn't get cupcakes out of my mind. I had to prove that I could make a cupcake at least as delicious and whimsical as those two Greek sisters are doing in DC.
So I did.
Lime cupcakes with blackberry buttercream.
I followed the Tender White Cake recipe on the back of the King Arthur cake flour box, substituting fresh lime juice and zest for the almond extract. I can't imagine a more perfect white cupcake recipe. It's a gorgeous sponge whipped up with plenty of butter and egg whites, which makes the mixing process easier because you don't have to be so worried about overbeating.
I cooked the blackberries over medium heat until they broke down into a sauce. I strained them, and then beat the syrupy purple juice with a lot of butter this time, since the lack of butter was the problem in the raspberry recipe. I've made "dump icing" pretty much my whole life, so I just whipped the butter, whipped in the blackberry concentrate, and then added powdered sugar until I liked the consistency.
I did it. They are amazing. And my photos aren't bad this time, either! Take that, DC Cupcakes.