Instructions

• Preheat oven to 350°F. Line a 12-cup muffin tin with paper liners and lightly spray the liners with non-stick spray (optional).
• In a microwave-safe bowl, combine 3 tablespoons coconut or canola oil, 1 stick (8 tablespoons) unsalted butter (melted and slightly cooled), and 1/2 cup semi-sweet chocolate chips. Microwave in 30-second increments, stirring between each increment, until fully melted and smooth. Alternatively, melt over very low heat on the stovetop. Set aside to cool slightly.
• In a medium bowl, whisk together 3/4 cup plus 2 tablespoons all-purpose flour (not packed), 1/2 teaspoon baking soda, 1 teaspoon baking powder, 1/2 cup unsweetened cocoa powder, and 1/2 teaspoon salt until evenly combined. Set aside.
• In a large bowl, whisk 2 large eggs plus 1 large egg yolk, 1 cup granulated sugar, and 1 teaspoon vanilla until smooth.
• Add the cooled chocolate mixture to the egg mixture and whisk until smooth.
• Add half of the dry ingredient mixture to the wet mixture and stir until just combined. Add half of the 1/2 cup full-fat sour cream and stir until just combined. Repeat with the remaining dry mixture and the remaining sour cream, stirring only until just combined each time.
• Quickly stir in 1/2 cup hot coffee or hot water until evenly combined. Do not overmix.
• Divide the batter among the 12 prepared liners, filling each about 3/4 full. Bake for 16–18 minutes, or until a toothpick inserted in the center comes out clean. Transfer cupcakes to a wire rack and cool completely before stuffing and frosting.
• While the cupcakes cool, make the raspberry puree: in a small saucepan combine 1 1/4 cups frozen (or fresh) raspberries and 2 tablespoons lemon juice. Bring to a simmer over medium heat, stirring and breaking up the berries, until the mixture thickens and can coat a spoon (it will resemble jam). You should end up with about 1/4 cup raspberry puree. Remove from heat and cool completely.
• When cupcakes are completely cool, use a small sharp knife to cut a small cavity from the center of each cupcake and reserve the removed pieces. Divide 1/4 cup Nutella evenly among the 12 cupcakes and spoon or pipe about 1 teaspoon Nutella into each cavity. Replace each reserved cake piece to cover the filling.
• Make the raspberry frosting: place 2 sticks (8 ounces) very soft unsalted butter in a large bowl or the bowl of a stand mixer. Beat on medium-high until smooth, about 2 minutes. Add the cooled raspberry puree and beat until combined, about 1 minute.
• With the mixer on low speed, add 3 1/2 cups sifted confectioners' sugar one cup at a time, incorporating between additions. Add 1 tablespoon heavy cream and 1/2 teaspoon salt. Increase mixer speed to high and beat for 2 minutes, until the frosting is thick and fluffy. (If needed, you may adjust texture very slightly using the parenthetical options listed with the ingredients.)
• Frost the filled cupcakes as desired and top with up to 1/4 cup fresh raspberries for decoration, if using.