My bestest bud, Terri, requested “black raspberry anything” for her bridal shower. I ultimately devised a black raspberry buttercream that’s perfect for cupcakes—especially ones concealing more berries. Although black raspberry season is short, some orchards ship frozen berries year-round (see Resources)—and boy, are they worth it! Blackberries or red raspberries can be used in a pinch.
Makes 12 cupcakes
Difficulty: Easy
Make Ahead and Storage: The cooled unfrosted cupcakes can be stored tightly wrapped, for up to 2 days at room temperature. The buttercream can be made up to 1 week ahead and stored in an airtight container in the refrigerator (see sidebar for how to reconstitute before using). The frosted cupcakes should be eaten within 2 days.
1. Preheat the oven to 350°F/ 175°C, with a rack in the middle. Grease the cavities of a muffin pan or line with paper liners.
2. Make the cupcakes: In the bowl of a stand mixer fitted with the paddle attachment (or in a large bowl, using a hand mixer), cream the butter, granulated sugar, and lemon zest on medium-low speed until light and fluffy, 4 to 5 minutes.
3. Add the eggs one at a time, mixing until each is fully incorporated before adding the next. Scrape the bowl well.
4. In a medium bowl, whisk together the flour, baking powder, and salt. In a container with a spout (such as a 2-cup liquid measure) or a small bowl, whisk together the buttermilk and lemon juice to combine.
5. Add half the flour mixture to the butter mixture and mix on low speed just until combined. Add half the buttermilk mixture and mix just until combined. Repeat with the remaining flour mixture, followed by the remaining buttermilk mixture, mixing just until the ingredients are uniformly incorporated and the batter is smooth.
6. In a small bowl, toss the berries with the cornstarch to coat. If the berries don’t appear fully coated, add more cornstarch 4 g / 1 teaspoon at a time.
7. Scoop the batter into the prepared cups, filling each one about three-quarters full (I use a #16 / ¼-cup scoop, but you can just wing it). Drop a few raspberries into each cup and press them gently into the center (not down to the bottom) of the batter.
8. Bake the cupcakes until their centers spring back slightly when touched, 18 to 20 minutes. Let cool completely in the pan.
9. Make the buttercream: Combine the berries and granulated sugar in a medium saucepan and bring to a simmer over medium heat. Cook until the berries break down and are very juicy, 5 to 7 minutes. Mash the fruit with a potato masher or the back of a spoon.
10. Strain the berry juice into a small saucepan and bring to a simmer over medium heat. Simmer until the juice is reduced to 81 g / ⅓ cup. Let cool to room temperature (you can throw it in the fridge to speed this up).
11. Place the butter in the bowl of a stand mixer fitted with the paddle attachment (or use a large bowl and a hand mixer). Beat the butter for 1 minute, then gradually add the powdered sugar and cream the mixture on medium-low speed until light and fluffy, 4 to 5 minutes.
12. Add the reduced berry juice, vanilla, and the cream, if using, and beat until well combined, scraping the bowl well to make sure the juice has been evenly incorporated.
13. Frost the cupcakes: To pipe on the buttercream, transfer about half of it to a pastry bag fitted with a large star tip (such as #838 or #848; see Pastry Bags) and pipe a mound of frosting onto each cupcake, refilling the bag with the remaining frosting when you get low. Or spoon a dollop of frosting atop each cupcake and spread it with a small offset spatula.
✻ Why It Works
Tossing the berries with cornstarch helps prevent them from sinking to the bottom of the batter. Keeping them suspended in the center is significantly prettier, ensures even flavor and texture in each bite, and prevents the burnt bottoms that can result from an overrun of fruit juice.
★ Pro Tip
Using a fruit juice reduction to flavor buttercream is a great technique that works as well with an Italian buttercream as it does with a simple buttercream like this one. Use a reduction made from fresh or frozen fruit, like berries or sliced stone fruit such as peaches, plums, apricots, or cherries. For a buttercream flavored with citrus, pomegranate, or tropical fruit, you’re better off reducing pure fruit juice: Substitute 475 g / 2 cups juice for the fruit and skip the straining step unless the juice is very pulpy.