Line the base and sides of an 18cm springform tin with baking paper. Blitz the biscuits with the cinnamon and salt to fine crumbs, keep 2 tablespoons back for decorating, and stir the rest into the melted butter.

Press firmly into the base of the tin, using the back of a spoon to get it flat and even, and chill 20 minutes.

Soak 3 gelatine leaves in cold water for 5 minutes. Warm the milk until steaming, squeeze out the gelatine and stir it in until fully dissolved. Let it cool until just warm but still fluid.

Beat the mascarpone, pumpkin purée, icing sugar, spices and vanilla until smooth. Beat gently; mascarpone splits if you work it hard.

Stir a large spoonful of the pumpkin mixture into the warm gelatine milk first, then pour that back into the main bowl and mix quickly and thoroughly. Tempering this way stops the gelatine setting into threads.

Whip the cold cream to soft peaks and fold it through in three additions, keeping as much air as you can.

Pour over the chilled base, smooth the top with a palette knife and refrigerate at least 5 hours, ideally overnight, until firm.

Make the glaze. Soak 2 gelatine leaves. Warm the orange juice, sugar and apricot jam until the sugar dissolves, take off the heat, squeeze out the gelatine and stir it in. Cool to room temperature, until syrupy but still pourable.

Pour the glaze over the set mousse and tilt the tin gently so it finds the edges in an even sheet. Chill 1 hour more to set the glaze.

Release the tin, peel the paper from the sides, and press the reserved crumbs around the bottom edge.

Finish with a swirl of whipped cream, a scattering of crumbs and chocolate leaves set on top.