Start by preheating the oven to 400°F / 200°C. Prepare a 7” / 18cm round springform cake pan by greasing the interior with a little butter, and placing a parchment paper circle in the bottom (I find it easiest to trace the bottom of the cake form, then cut it out to fit perfectly).
Make the hemp cream by placing the hemp seeds and water in a blender and blend on high for 30 seconds, or until the cream is smooth. Set aside.
In a food processor, blend hemp seeds until they’re the texture of sand (but don’t blend too much or you’ll end up with hemp butter!). Add the flour, baking powder, and salt. Pulse to blend and set aside.
Melt the butter over low heat and let cool. Meanwhile, beat the eggs and sugar together until light and fluffy (either with an electric mixer or your arm muscles!). Stir in the flour mixture, then fold in the butter, hemp cream and vanilla. Pour batter into the prepared springform pan and place in the oven to bake for 20 minutes. Then reduce oven temp to 350, and bake for another 20 minutes until a toothpick inserted comes out clean.
While the sponge is baking, make the topping by toasting the coconut in a large skillet over medium heat (work in batches if necessary, and toast the two types of coconut separately). Once golden and fragrant, set aside. Melt the butter over low heat, then stir in the coconut sugar. Stir frequently until they combine into a thick caramel (this make take a few minutes, but keep stirring!). Add the hemp cream and vanilla, stir to incorporate. Remove from the heat, then add the flaky salt, toasted coconut, and fold to thoroughly combine.
Once the sponge is baked, remove from the oven and spread the topping over as evenly as possible. Place back int the oven for another 5 minutes, just until the topping is bubbling. Remove from oven and let cool completely, then place in the fridge to firm up, at least 2 hours. Remove cake from the fridge, then using a sharp knife, cut around the edge to release caramel that is stuck to the sides. Unlock the springform to reveal! Slice, say thank you, and enjoy. Leftovers can be stored covered, at room temperature for about a week.