Prep the Base: Preheat your oven to 160°C (140°C fan). Line the base of a 20cm springform tin with parchment paper. Crush the digestive biscuits into fine crumbs — you want them to look like wet sand. Stir in the melted butter and 1 tablespoon of caster sugar until the mixture feels uniformly damp and clumps together when pressed. Press this firmly into the base of the tin using the bottom of a glass. Bake for 10 minutes, until it smells toasty and the edges are just beginning to darken. Set aside to cool.

Melt the Chocolate: While the base cools, place the finely chopped dark chocolate in a heatproof bowl over a pan of simmering water. Stir gently until it is completely smooth and glossy. Remove from the heat and let it cool for 5 minutes — it should feel warm to the touch but not hot.

Make the Cheesecake Filling: In a large mixing bowl or the bowl of a stand mixer, beat the cream cheese on a medium speed until it is completely smooth and free of lumps — this should take about 2 minutes. Add the 150g of caster sugar and the vanilla extract, then beat again until the mixture looks light and fluffy. Add the eggs one at a time, beating on low after each addition. The mixture will look like a thick, creamy custard. Finally, pour in the double cream and beat until just combined. Do not overmix.

Assemble the Layers: Pour about two-thirds of the cheesecake filling over the cooled base. Drizzle the melted chocolate over the filling, then use a knife to swirl it gently through the mixture — you want ribbons of chocolate, not a fully blended colour. Gently pour the remaining cheesecake filling on top, spreading it evenly. The surface should look pale and smooth.

Bake the Cheesecake: Place the springform tin on a baking tray. Bake for 45–55 minutes. The cheesecake is done when the edges look set and slightly puffed, but the centre still has a slight wobble when you gently shake the tin. The surface should be a very pale gold, and you might see a few tiny cracks forming at the edges. Turn the oven off, crack the door open, and leave the cheesecake inside to cool for 1 hour. This gentle cooling prevents a dramatic collapse.

Chill and Top: Once the cheesecake has cooled to room temperature, refrigerate it for at least 4 hours, or overnight. When you're ready to serve, make the caramel: melt the butter and brown sugar in a small saucepan over a medium heat. Stir until the sugar dissolves and the mixture is bubbling and amber-coloured. Remove from the heat and carefully whisk in the double cream and sea salt. The sauce will hiss and steam — that's fine. Let it cool for 5 minutes until it thickens slightly. Pour the caramel over the chilled cheesecake, then scatter over the toasted pecans. Finish with a few extra shavings of dark chocolate if you like.

Slice and Serve: Run a sharp knife under hot water and dry it before slicing. This gives you clean, neat slices. The contrast of the creamy, cool cheesecake against the sticky caramel and crunchy pecans is truly something special.