In celebration of her birthday, my good friend Angela threw a picnic for all her friends. I had a pile of blackberries at the ready, and so decided to experiment with a springtime cupcake recipe.
I started with Cook’s Illustrated white cake, but made some modifications. For the frosting, I made a standard buttercream icing, with blackberry and lemon zest. Spoiler alert: They are super-pink!
What you need for the cupcakes:
4 6 oz packs of blackberries
1/3 cup milk, at room temperature
6 large egg whites, room temperature
2 tsp lemon juice
2 1/4 cup cake flour, sifted
1 3/4 cup sugar
4 tsp baking powder
1 tsp salt
1 1/2 sticks (12 tblsp) unsalted butter, softened
What you need for the icing:
2 sticks unsalted butter, softened
1/2 tsp vanilla
1/4 tsp almond extract
3 1/2 cups confectioner’s sugar
(optional) 1 tblsp meringue powder or cream of tartar
1/4 tsp salt
1/4+ cup blackberry puree (from the puree above)
1 tsp lemon zest
What to do:
– Preheat the oven to 350 degrees and line two muffin pans
– Puree the blackberries in a food processor or blender (I had only a mini-chopper, and had to do this in batches). Scrape the puree into a fine mesh sieve set over a bowl. Use a flexible spatula to push the blackberries through the sieve, leaving seeds behind. You should be left with 2/3 – 1 cup of clean, filtered puree. Set 1/4 or 1/2 cup aside for the frosting!
(Option: We saved a few whole blackberries to bake right in the centers of some cupcakes, and this was a tasty surprise for some people)
– In a small bowl, combine the puree, milk, egg, and lemon juice. Whip them up with a fork until they’re well-blended. Set aside.
– In a large bowl, add sifted flour, sugar, baking powder and salt and mix (with hand mixer or stand mixer) to combine. Continue beating at slow speed and add the butter. Mix until combined and you’ve got moist crumbs.
– Add the liquids (over there in your small bowl) and beat at medium speed for about 1 minute or until evenly combined, scraping down the sides when you need to.
– Fill cupcake liners ~3/4 full.
(If you’re including whole blackberries in your cupcake centers, as we mentioned in the Option above, drop them into the centers of the cups at this point!)
– Bake for about 20 minutes or until a toothpick inserted into a cupcake center comes out clean. Set out to cool.
To make the frosting:
– Cream the butter and extracts until smooth using your mixer.
– Mix in confectioner’s sugar, meringue powder or tartar, if you’re using it, and the salt. Beat 2-3 minutes on high.
– Add the blackberry puree and beat for another minute. If the texture isn’t quite what you want, you can add confectioner’s sugar (to thicken) or water (to thin).
The frosting is pretty sweet, so you’ll likely only need a thin layer on each cupcake.
The width viewed in the top image is ~ 100 microns (0.1 mm) and the bottom ~700 microns (0.7 mm). Can you guess what it is?
Note: Some of my DC friends have seen this before, so I ask them to kindly let others guess.
Update, 5:05p: Nice job, Callan! Staples on end is right:
A year ago this week, I was in Iceland, along with three very good friends. It was 20% work, in that I did a site visit to the Iceland Deep Drilling Project, and 80% fun, in that we drank good beer, walked between tectonic plates, floated around the Blue Lagoon for 5 hours, and generally had an amazing (and cold and windy) time.