Preheat your oven to 325 degrees. Brew the coffee. While the coffee is brewing, spray the bundt pan with cooking spray and then dust with cocoa powder if needed. Do this well to ensure the bundt cake comes out of the bundt pan perfectly.
In a microwave safe bowl, melt the butter for 20 seconds. In a large mixing bowl, mix the melted butter with the coffee, buttermilk, cocoa powder and cinnamon. Stir with a wire whisk. Once everything is combined, add the sugar and whisk until it has dissolved.
In a separate bowl, combine your dry ingredients: the flour, baking soda, and salt. Mix gently.
Whisk the eggs (one at a time) and vanilla into the chocolate mixture. Slowly add the flour mixture and continue to mix. Once all of the ingredients have been combined you will be left with a batter with the consistency of a slightly thick soup.
Pour the batter evenly into the bundt pan and bake for about 50 minutes or until a toothpick inserted comes out clean.
Remove the bundt pan from the oven and let cool for at least 20- 30 minutes. Once cooled, gently run a butter knife or fork around the sides of the cake to gently remove from the pan. Invert your bundt cake onto a cooling rack or cake plate and let cool before dusting with confectioners' sugar.