Prep sweet potato: If starting with raw sweet potatoes, you'll need around 700g. Roast them on a lined baking sheet for 40-45 minutes at 425°F (220°C) until soft. Cool to room temperature and puree or mash with a fork. You'll need 450g of cooked sweet potato puree in total.

Preparation: Line the sides and base of a 7.5 or 8-inch springform cake pan with parchment paper. Preheat your oven to fan-forced 170°C/340°F or conventional 180°C/356°F.

Mix dry ingredients: Sift the flour, cocoa powder, baking powder, and sea salt into a bowl and stir to combine. Set aside.

Mix wet ingredients: In a separate large bowl, whisk 250g sweet potato puree, non-dairy milk, apple cider vinegar, coconut sugar, olive oil, espresso, and vanilla.

Make the batter: Add half the dry ingredients to the wet and whisk until combined. Then switch to a rubber spatula, and gently fold in the other half of the dry ingredients.

Bake: Add the batter to the prepared pan and bake for 50 minutes. To check for doneness, insert a skewer or toothpick into the center, it should come out almost clean with a few crumbs. If there is still wet batter on the skewer, continue to bake for another 5 minutes as needed.

Cool: Allow the cake to cool in the tin for 10 minutes, then carefully remove the pan and transfer to a wire rack to cool completely.

Frosting: Add all the ingredients to a food processor and blitz until smooth and frost the cooled cake.