I LOVE tahini! This cake is super moist - as if your favourite boxed cake got a major upgrade.
Make the crumble: Combine the flour, brown sugar, cinnamon, and salt in a medium bowl. Mix until well blended. Add the butter and, using your fingers, work the butter into the flour mixture until large clumps form.
Add the tahini and vanilla and stir with a spoon until incorporated. Add the crumbled halva, stirring to combine, and refrigerate.
Make the cake: Preheat oven to 180°C. Line an 20cm springform tin with baking parchment and coat with cooking spray.
In a large bowl, sift together the flour, cocoa, baking powder, salt, and bicarbonate of soda. Add the granulated sugar and whisk until well combined.
In a separate medium bowl, whisk together the eggs, milk, sour cream, vegetable oil, tahini, and vanilla. Add the wet ingredients to the dry ones and whisk until blended and no streaks of flour remain. Whisk in the boiling water, stirring until smooth.
Scrape the batter into the tin, smooth the top, and bake for 20 minutes. Scatter the crumble on top of the cake and continue to bake until a cake tester inserted in the centre comes out clean , 20 - 25 minutes. Cool for at least 30 minutes, then remove from the tin.
If making the melted chocolate, 5 - 10 minutes before serving place the chopped chocolate in a microwave-safe bowl and microwave on high in 30-second intervals, stirring in between, until the chocolate is fully melted. Drizzle the chocolate over the top and sprinkle with sesame seeds before serving, if desired.
Recipes extracted from ‘Eitan eats the World’ (Clarkson Potter)