1. First, you'll want to preheat your oven to 350 degrees Fahrenheit. This is a crucial step to ensure even baking. While that's happening, line your cupcake molds with paper liners, which should fit about 24 to 26 cupcakes.
2. Next, grab a large mixing bowl. In it, combine melted coconut oil, large eggs, whole milk, plain Greek yogurt, granulated sugar, and vanilla extract. Use a whisk or an electric mixer to beat these ingredients together until you have a smooth mixture.
3. Now, it’s time to incorporate the dry ingredients. Add all-purpose flour, unsweetened cocoa powder, baking powder, baking soda, and kosher salt to the bowl. Mix until all the dry ingredients are just combined. Be careful not to overmix, as this can lead to tough cupcakes.
4. Slowly mix in the hot black coffee. This will make your batter quite thin, which is okay! If you're using them, stir in the semi-sweet chocolate chips gently.
5. Now, take your batter and divide it evenly among the prepared cupcake molds. I like to use an ice cream scoop for this—it makes the process mess-free and ensures uniform sizes.
6. Place the cupcake tray in the preheated oven. Bake for 25 to 30 minutes. You'll know they're done when the tops are set and no longer wiggly in the center. A toothpick inserted should come out clean.
7. Once baked, remove the cupcakes from the oven and let them cool in the tray for about 10 minutes. After that, transfer them to a wire rack to cool completely.
8. While your cupcakes are cooling, let’s turn our attention to the frosting. In a new mixing bowl, beat the salted butter until it’s light and fluffy, about 2 to 3 minutes. This step is essential for achieving the right texture.
9. Add powdered sugar to the butter and mix until just combined. Pour in the melted dark chocolate, vanilla extract, and 1 tablespoon of warm milk. Beat until fully combined and fluffy. If it’s too thick, you can add more milk, one tablespoon at a time, until you reach your desired consistency.
10. Finally, it’s time to frost your cupcakes! Using a knife or a piping bag, frost each cooled cupcake with the chocolate frosting. Decorate with sprinkles or chocolate shavings as desired. Enjoy every bite!