Preheat oven to 325 degrees. Fill cupcake pan with liners. Set aside
In a medium saucepan, melt butter over medium heat. Whisk in the cocoa, espresso powder, chocolate chips, sugar and 1 1/2 cups water, whisking until smooth after each addition. When melted and combined, remove from heat and set aside for 5 minutes.
In a medium bowl, combine flour, cinnamon, baking soda, salt, cayenne, and chili powder; whisk until combined. Set aside.
Pour chocolate into a large mixing bowl. Add eggs and vanilla, whisking until fully incorporated. Stir in mixture and mix with a spoon or rubber spatula. Scoop batter into prepared liners.
If batter becomes too thick between batches, add a small amount of water to thin.
Bake for 13 minutes, until toothpick inserted into center comes out clean. Remove from oven and cook in pan for 3-4 minutes before transferring to rack to cool completely.