Preheat the oven to 340°F.

Line and lightly grease three 6-inch baking tins.

Mix together milk and vinegar; set aside to thicken to form buttermilk (soy milk works best).

Once thickened, pour into a large mixing bowl and add the remaining wet ingredients.

Sift in the dry ingredients using a sieve.

Gently mix until just combined.

Pour the batter into the tins and bake for 24-28 minutes or until well risen and cooked through.

While the sponge cools, make the frosting.

In a stand mixer, cream the butter on medium-high until light and fluffy (about 5 minutes), scraping down the bowl and paddle a few times. Add the powdered sugar bit by bit, scraping down the bowl and paddle between intervals. Then add the cocoa powder. Mix until fully incorporated, about one minute. Mix in the caramel and milk until fully combined.

Make the caramel by combining the ingredients. Depending on your tahini, you may need more coconut oil; keep adding until it reaches your desired consistency.

Once the cakes are cool, layer them with the frosting and caramel.