Step 1

Preheat oven to 160°C. Grease a baking tray and line with baking paper. Grease base and side of a 16.5cm springform cake pan and line with baking paper.

Step 2

Place white chocolate on prepared tray and roast for 10 minutes or until very light golden. Chill until cold, then coarsely chop.

Step 3

To make cake, in a stand mixer fitted with the paddle attachment, beat butter, caster sugar and vanilla until pale and fluffy. Add eggs, 1 at a time, beating well between each addition. Fold through cocoa, flour, baking powder, buttermilk, coffee and chocolates.

Step 4

Spread batter into prepared pan and bake, covering with foil halfway, for 1 hour 40 minutes or until a skewer inserted into cake comes out clean. Stand in pan for 10 minutes, then transfer, top-side up, to a wire rack and stand until completely cooled.

Step 5

Meanwhile, for the tahini cream, soak gelatine leaves in water for 5 minutes to soften. Combine milk, cream and sugar in a saucepan over high heat and bring to a simmer. Whisking constantly, gradually add hot milk mixture to egg yolks in a heatproof bowl. Return egg mixture to saucepan, reduce heat to low and cook, stirring constantly, for 3 minutes or until egg mixture coats the back of a wooden spoon. Squeeze excess liquid from gelatine and stir through egg mixture, then whisk in chocolate and tahini until chocolate is melted and well combined.

Step 6

Transfer chocolate mixture to a heatproof bowl, cover surface directly with plastic wrap and chill for 5-6 hours or until firm. Whisk to firm peaks (if too soft, freeze for 10 minutes; if too firm, stand at room temperature for 20 minutes).

Step 7

To make the sesame sprinkle, place sesame seeds in a blender and whiz until finely chopped. Transfer to a bowl and stir through brown sugar and 1/2 tsp salt flakes.

Step 8

For the butterscotch sauce, place sugar and butter in a saucepan over medium heat and cook, stirring constantly, for 2-3 minutes or until sugar dissolves. Whisking constantly, slowly add cream and cook, stirring regularly, for 1 minute or until smooth and combined. Remove from heat, add 1 tsp salt flakes and stir to dissolve.

Step 9

Place cake on a serving plate, top with two-thirds tahini cream, scatter with macadamias and drizzle with some butterscotch sauce. Scatter over some sesame sprinkle and serve with remaining butterscotch, tahini cream and sprinkle.