Preheat the oven to 180ºC (350ºF) and grease, line, and dust with cacao powder three 20cm (8 in) cake tins.
In a large bowl, whisk together the flour, cacao powder, coconut sugar, baking soda, baking powder, salt, and espresso powder. Set aside.
In a separate bowl, whisk together the oil, egg, vanilla, milk, and yogurt until well combined.
Make a well in the dry ingredients and pour the wet ingredients into it. Mix until all the dry ingredients disappear – the batter will be very thick.
Slowly pour in the hot coffee, whisking continuously until incorporated.
Divide the batter evenly between the 3 prepared tins and bake for 24-27 minutes until a cake tester comes out clean or with a few crumbs attached. Place the tins on a wire rack and allow the sponges to cool completely in the tins.