Instructions:

• Step 1: Preheat your oven to 350°F (175°C). Line your muffin tin with cupcake liners.
• Step 2: In a large mixing bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking powder, baking soda, granulated sugar, and salt until well combined.
• Step 3: In a separate bowl, mix the sour cream, vegetable oil, vanilla extract, and eggs until smooth.
• Step 4: Add the wet mixture to the dry ingredients and mix until just combined. Be careful not to overmix; a few lumps are okay.
• Step 5: Slowly stir in the boiling water until the batter is smooth. The batter will be quite thin, but this is normal and essential for moist cupcakes!
• Step 6: Pour the batter into the lined muffin tin, filling each liner about two-thirds full.
• Step 7: Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the center comes out clean.
• Step 8: Once baked, remove the cupcakes from the oven and let them cool in the tin for about 5 minutes before transferring them to a cooling rack.
• Step 9: In a large mixing bowl, use an electric mixer to beat the softened salted butter until creamy. Gradually mix in the cocoa powder, followed by the powdered sugar, vanilla extract, and heavy cream. Beat until the frosting is smooth and fluffy.
• Step 10: Once the cupcakes are completely cooled, use a piping bag or a spatula to frost each cupcake generously.
• Step 11: If desired, sprinkle chocolate sprinkles on top for a festive touch.