For the crust:
32 Oreo cookies in crumbs
5 1/3 tbsp. unsalted butter, melted and cooled
Small pinch of salt
For the crunch:
125ml/½ cup salted peanuts, chopped
125ml/½ cup mini chocolate chips
2 tsp. sugar
½ tsp. espresso powder
¼ tsp. ground cinnamon
For the filling:
500ml/2 cups heavy cream
375 ml/1¼ cups confectioners sugar, sifted
350g/12 oz. cream cheese, at room temperature
375 ml/1½ cups creamy peanut butter
2 tbsp. whole milk
60ml/¼ cup salted peanuts, chopped
For the topping:
125ml/½ cup heavy cream
115g/4 oz. bittersweet chocolate, finely chopped
125ml/½ cup salted peanuts, finely chopped
To make the crust, preheat the oven to 180°C / 350°F. Butter a 9-inch springform pan and place it on a baking sheet. Combine the Oreo crumbs, melted butter and salt in a small bowl. Toss with a fork to moisten all of the crumbs. Press into a thin layer covering the bottom and sides of the pan. Freeze for 10 minutes. Bake in the preheated oven for 10 minutes, then put it on a wire rack and let cool completely before filling.
To make the crunch, in another small bowl combine ½ cup of the chopped peanuts, mini chocolate chips, sugar, espresso powder, cinnamon and nutmeg. Toss with a fork to mix and set aside.
To prepare the filling, whip 2 cups of the cream. Beat in ¼ cup of confectioners’ sugar.. Put into a bowl and refrigerate until needed.
Wipe out (do not wash) the mixer bowl, replace the whisk with the paddle attachment, and beat the cream cheese with the remaining 1 cup of confectioners sugar on medium speed until the cream cheese is smooth. Beat in the peanut butter, milk, and ¼ cup of the chopped peanuts.
Stir in about 1/4 of the whipped cream. Stir in the crunchy peanut mixture, then put in the remaining whipped cream. Scrape the mousse into the crust. Refrigerate for at least 4 hours or overnight; cover with plastic wrap as soon as the mousse firms.
To finish, put the chopped chocolate in a heatproof bowl set over a saucepan of water. Leave the bowl over the water until the chocolate softens and starts to melt, about 3 minutes; remove the bowl from the saucepan. Bring the ½ cup of cream to a full boil. Pour the cream over the chocolate and stir together until it is completely blended and smooth.
Pour it over the cake and smooth it. Scatter the peanuts over the top.