Make the Cupcakes

1. Preheat oven to 175°C (347°F) and line a 12-cup muffin pan with liners.
2. In a large bowl, cream butter and sugar until light and fluffy.
3. Gradually add eggs, beating well after each, then mix in vanilla extract.
4. Slowly pour in milk and coffee, mixing until combined.
5. Sift together flour, cocoa powder, baking powder, and salt, then fold into the batter using a spatula. Do not overmix.
6. In a small bowl, mix vinegar and baking soda (it will bubble), then fold into the batter.
7. Fill cupcake liners ¾ full with batter.
8. Bake for 20-22 minutes, or until a toothpick inserted in the center comes out clean.
9. Let cupcakes cool completely before filling and frosting.

Make the Raspberry Sauce

10. In a saucepan, cook raspberries, lemon juice, and sugar over medium heat for 10 minutes until slightly thickened. Let cool. (Alternatively, use raspberry jam.)

Make the Raspberry Buttercream

11. Using a stand or hand mixer, cream butter for 3 minutes until light and fluffy.
12. Gradually add powdered sugar, mixing on low speed, then whip for 4 minutes on medium-high.
13. Add raspberry reduction, lemon juice, vanilla extract, salt, and heavy cream while mixing on low. Whip for 1 more minute until smooth.

Assemble the Cupcakes

14. Make a small hole in each cooled cupcake and fill with 1 tbsp raspberry sauce.
15. Transfer frosting to a piping bag and decorate cupcakes as desired.
16. Garnish with fresh raspberries and mint if desired.
17. Serve fresh. Store leftovers in an airtight container in the fridge for 2-3 days. Bring to room temperature before serving.