Heat a large saucepan over medium-high heat, scatter 140gm sugar over the base and cook until starting to turn caramel, then swirl pan occasionally to cook evenly to a light golden caramel (2-3 minutes). Remove from heat and add 300gm cream, 115gm glucose and vanilla bean paste. Return to heat and bring to the simmer, whisking to dissolve any lumps (3-4 minutes). Add peanut butter, then butter and whisk to combine. Squeeze excess water from gelatine and whisk into the hot liquid. Remove from heat and strain through a fine sieve into a large bowl.
Place egg yolks in an electric mixer and whisk until pale and tripled in volume (2-3 minutes). Bring remaining sugar, remaining glucose and 30ml water to the boil in a small saucepan over high heat and cook until it reaches 117C, then, with the mixer running on medium speed, pour sugar mixture into egg yolks. Whisk for 3 minutes, then whisk the yolk mixture into the peanut butter mix and cool completely. Fold the whipped cream into the mixture, pour into a 30cm x 15cm plastic tray lined with baking paper, cover with plastic wrap and freeze overnight.
For butterscotch sauce, heat a saucepan over medium-high heat, scatter sugar over the base and cook until starting to turn light golden caramel, swirling the pan occasionally to cook evenly (2-3 minutes). Meanwhile, bring 50ml water and 1 tsp fine salt to the boil in a separate small saucepan. Once sugar is caramel, reduce the heat and add boiling water to the caramel along with the butter, whisking until dissolved, whisk in the brown sugar and cream together. Don’t overcook – it becomes thick once cool.Strain the mixture through a fine sieve and set aside to cool to room temperature (30-40 minutes).
For chocolate mousse, whisk egg yolks in a bowl with sugar and powdered glucose. In a small saucepan, bring the milk and 100ml cream to the boil. Allow to cool slightly (5 minutes), then pour into egg mixture, whisking to incorporate. Return the custard to the saucepan and stir over low heat until it starts to thicken (5-7 minutes). Remove from the heat and set aside. Melt chocolate in a bowl over
a saucepan of boiling water, then mix the custard into the chocolate a third at a time. Whisk remaining cream to soft peaks, and fold into chocolate mixture. Transfer to a container and store covered in the fridge.
To serve, turn the parfait out onto a piece of baking paper. Cut the parfait into 6cm-square pieces with a hot knife and return to the freezer immediately. If the parfait is too cold to cut leave it out for 5 minutes to soften up a bit. When you wish to serve, cool the plates in the freezer for an hour or so. Place a piece of parfait on each plate. Top with a quenelle of chocolate mousse, drizzle with caramel sauce and top with crushed peanuts and serve.