1-Step 1: Bring Ingredients to Room Temperature Start by removing the buttermilk and eggs from the refrigerator about 30 minutes before you plan to bake. Room temperature ingredients blend more smoothly and evenly, which creates a better batter texture. Cold ingredients can cause the batter to seize or not mix properly, leading to uneven baking. If you are short on time, you can warm the buttermilk slightly in the microwave for 15 seconds and place the eggs in a bowl of warm water for 5 minutes. Do not let the buttermilk get hot, as this can affect how it works with the leavening agents.

2-Step 2: Preheat and Prepare Your Pan Preheat your oven to 350 degrees F. This temperature allows the cupcakes to bake evenly without drying out. While the oven heats, line a 12-well muffin tin with paper cupcake liners. If you are baking multiple batches, prepare a second tin or wash and dry the first one between batches. Proper oven temperature is crucial for cupcakes that rise correctly. If your oven runs hot or cold, consider using an oven thermometer to check the actual temperature. This simple tool can make a big difference in your baking results.

3-Step 3: Mix the Dry Ingredients In a medium bowl, whisk together the flour, sugar, cocoa powder, baking powder, baking soda, and kosher salt. Whisking blends these ingredients thoroughly so they distribute evenly throughout the batter. This step only takes about 30 seconds but makes a real difference in the final texture. Set this bowl aside while you prepare the wet ingredients. Having your dry ingredients ready keeps the mixing process organized and prevents you from accidentally skipping any ingredients.

4-Step 4: Create the Wet Mixture In a large bowl, whisk together the hot water and hot chocolate mix until smooth. This step blooms the cocoa flavors and ensures no lumps remain. The hot water helps dissolve the mix completely for the best flavor distribution. Add the buttermilk, canola oil, and vanilla extract to the hot chocolate mixture. Whisk to combine everything evenly. The oil in this recipe keeps the cupcakes moist for days, unlike butter-based recipes that can firm up at room temperature. Add the eggs one at a time, whisking after each addition. This gradual incorporation helps the eggs blend smoothly into the mixture without overworking the batter.

5-Step 5: Combine Wet and Dry Ingredients Fold half of the flour mixture into the wet ingredients using a spatula or wooden spoon. Mix until just combined, meaning you stop when you no longer see streaks of dry flour. Then fold in the remaining flour mixture the same way. Important: Mix only until the ingredients are incorporated. Overmixing develops gluten, which creates tough, dense cupcakes with tunnels running through them. A few small lumps in the batter are perfectly fine.

6-Step 6: Fill the Cupcake Liners Divide the batter evenly among the 12 muffin cups, filling each liner nearly to the top. An ice cream scoop or large spoon works well for this task. Consistent filling ensures all cupcakes bake at the same rate. Do not worry about smoothing the tops. The batter will settle and spread on its own during baking, creating flat tops that are perfect for frosting.

7-Step 7: Bake and Cool Bake the cupcakes for 20 to 22 minutes, or until a toothpick inserted into the center comes out clean. Start checking at the 18-minute mark if your oven runs hot. The cupcakes should spring back lightly when touched and have slightly pulled away from the edges of the liners. Let the cupcakes cool in the muffin tin for 5 minutes before transferring them to a wire rack. Cool completely before frosting, as warm cupcakes will melt the butter in the frosting. For best results, these professional baking tips can help you achieve perfect results every time.

8-Step 8: Make the Marshmallow Frosting While the cupcakes cool, prepare the frosting. Start by softening the butter at room temperature. Beat the butter with the salt in a large bowl until smooth and creamy, about 2 minutes. Use an electric hand mixer or stand mixer for best results. Gradually add the powdered sugar, beating well after each addition and scraping down the bowl as needed. This gradual addition prevents sugar clouds and ensures smooth incorporation. Add the marshmallow fluff and vanilla extract. Beat until the frosting is smooth and fluffy, about 2 more minutes. The frosting should hold its shape when piped but still spread easily.

9-Step 9: Frost and Garnish Spread or pipe the frosting onto the completely cooled cupcakes. A piping bag fitted with a round or star tip creates a professional look, but a simple knife or offset spatula works just as well for a homey, rustic appearance. For the finishing touch, dust the frosted cupcakes with a little hot chocolate mix using a fine mesh strainer. Top with marshmallow bits or mini marshmallows for that authentic hot cocoa presentation.