Nutella Stuffed Chocolate Raspberry Cupcakes

Place the chocolate and cocoa powder in a medium heatproof bowl. Pour hot coffee over the mixture. Cover and let stand for 5 minutes. Whisk gently until smooth then set aside to cool completely.
Meanwhile, preheat the oven to 350°F. Line a standard 12-cup muffin tin with foil or paper liners.
In a small bowl, whisk the flour, sugar, salt, and baking soda together. Set aside.
Whisk the oil, eggs, vinegar, and vanilla into the cooled chocolate mixture until smooth. Stir in the flour mixture until smooth. Using a spring-loaded scoop or a large spoon, divide the batter evenly among prepared muffin cups.
Bake until cupcakes are set and firm to the touch, about 17 to 19 minutes. Let the cupcakes cool completely. Using an apple corer or pairing knife, remove a small section of the center of the cupcake, being careful not to slice through the bottom. Fill each hole with 1 heaping teaspoon of Nutella.

In the bowl of an electric mixer, beat the butter until light and fluffy. Add the vanilla. Gradually add the sugar, one cup at a time, beating well on medium speed. Add the raspberry preserves and beat until light and fluffy. For a more saturated color, add a few drops of red food coloring, if desired.
Transfer the buttercream to a piping bag fitted with a decorative piping tip. Pipe frosting directly onto the stuffed cupcakes. Serve or store at room temperature for a day or in an airtight container in the fridge for up to 3 days.