A rich, moist buttermilk chocolate cake is paired with a silky bittersweet chocolate Swiss meringue buttercream and filled with an easy homemade lemon curd in these fabulously addictive Double Chocolate Lemon Surprise Cupcakes!
Preheat the oven to 350°. Line two muffin tins with 18 cupcake liners.
In a medium bowl whisk together the flour, cocoa powder, espresso powder, baking powder and salt; set aside.
In the bowl of a stand mixer fitted with the paddle attachment beat the butter and sugar together on high until thick. Add the eggs one at a time, beating well after each addition. Add the vanilla with the last egg. Scrape down the sides of the bowl as needed. Add the melted chocolate and mix to incorporate.
Reduce mixer speed to low and alternately add flour mixture and buttermilk beginning and ending with flour, scraping down the sides of the bowl as needed. I did three additions. You want to stop mixing as soon as the last of the flour has been incorporated.
Scoop the batter into the prepared muffin tins. The batter should almost reach the top of the liner. Bake in preheated oven 15 to 20 minutes or until a toothpick inserted into the center comes out with a few clinging crumbs.
After 2 minutes, remove to a wire rack and let cool completely before filling or frosting.
To Prepare the Buttercream:
Follow the recipe for Swiss Meringue Buttercream but add 75 grams bittersweet chocolate (melted and cooled) after adding vanilla and salt.
Notes
Even though these were still relatively moist on day 3 with no icing, I would not recommend serving them that way. They are best when filled and iced as soon as possible and eaten on day 1 or 2.