Preheat the oven at 160ºC/320ºF conventional oven and line a 12-cup cupcake tray with 12 cupcake liners.
Start by boiling some water and weigh out the water so it can cool down a bit while preparing the other ingredients.
120 g boiling water
In a bowl, sift all of the dry ingredients together. Give it a stir to make sure everything has been combined.
160 g all-purpose flour, 200 g granulated sugar, 50 g unsweetened cocoa powder, 1 teaspoon instant espresso powder, ½ teaspoon baking powder, ½ teaspoon baking soda, ½ teaspoon salt
In another mixing bowl add all of the wet ingredients, including the water, and with a hand whisk, whisk them together until combined. Be sure to not mix the ingredients too vigorously so the eggs don’t get over mixed.
120 g sour cream, 18%, 75 g vegetable oil, 2 large eggs, 1 ½ teaspoon vanilla extract, 120 g boiling water
Slowly pour the wet ingredients into the dry while gently stirring it all together. Make sure there are no lumps left in the batter.
Divide the cake batter into the 12 cupcake liners and bake them for 20-23 minutes.
Let the cupcakes cool in the hot pan. After 5 minutes, gently remove the cupcakes from the cupcake pan and let them cool down completely.