Step 1

Preheat oven to 325 degrees. Line a 12-cup standard muffin tin with baking cups. Whisk together flour, baking powder, salt, and baking soda. In a heatproof bowl, whisk together sugar, cocoa, and chocolate. Whisk in cherry juice.

Step 2

Melt butter in a small saucepan over medium heat, then continue to simmer until bubbles recede and solids on bottom of pan begin to turn golden brown, about 6 minutes. Pour into sugar mixture; whisk until well combined and chocolate has melted. Whisk in eggs, then dry ingredients.

Step 3

Divide batter evenly among cups. Bake until tops spring back when lightly touched, 22 to 24 minutes. Let cool in tin 5 minutes; transfer to wire racks and let cool completely. Refrigerate at least 2 hours and up to 12 (this will help create clean cuts).

Step 4

Use a 1 1/2-inch heart-shaped cutter to remove a 3/4-inch-deep heart from each of 6 cupcakes (removing a bit of additional cake, if desired, to create more room for frosting). Fill a pastry bag fitted with a large, plain round tip (such as Ateco #with frosting. Pipe frosting to fill heart cutouts. Pipe 1/4 cup frosting on remaining cupcakes. Top frosted cupcakes with heart cutouts. Cupcakes can be stored in an airtight container at room temperature up to 2 days.