To make the crust

1. Preheat oven to 350 degrees.
2. In the bowl of a food processor, add cookies and hazelnuts and process until it becomes a fine crumb consistency. Add melted butter and process again to combine.
3. Pour crumbs into the bottom of a 9-inch springform pan and press to form an even layer.
4. Bake 10 minutes or until golden brown around the edges. (The center of the crust may still look soft to the touch – as the crust cools, it will firm up.)
5. Cool the crust completely in the springform pan on wire rack.

To prepare the mousse

1. In a small saucepan, combine white chocolate and ¼ cup of the heavy cream. Stirring constantly, heat until the chocolate fully melts. Remove from heat and set aside to cool.
2. Pour the milk into a small, wide microwave-safe bowl. Very slowly sprinkle the gelatin over milk, allowing the gelatin to begin to absorb the milk before sprinkling more on top. (To avoid creating lumps with the gelatin, it’s important that you have a wide surface area of milk and sprinkle the gelatin slowly.) Allow the gelatin and milk to sit (do not stir) until the gelatin is fully softened – about 3 to 4 minutes.
3. Microwave the gelatin milk mixture at about 50% power until the gelatin completely melts. (About 15-40 seconds depending on your microwave. Start with 15 seconds and check in 5-10 second intervals to make sure you don’t scald the milk.) Once the gelatin dissolves, stir into the small saucepan with the white chocolate mixture. Refrigerate, stirring often, until the chocolate mixture cools and starts to thicken (but try not to let it thicken too much!).
4. While the chocolate mixture cools, in the bowl of a stand mixer, mix the cream cheese, sugar, salt and malted milk powder until light and fluffy. Slowly add in the cooled and thickened white chocolate-gelatin mixture, mixing until combined.
5. In a separate mixing bowl, whip the remaining heavy cream until stiff peaks form. Fold the whipped cream into the cream cheese mixture by hand until blended.
6. Spoon the mousse mixture over the cooled crust, spreading evenly in the pan. Refrigerate until firm – at least 3 hours or overnight.
7. When ready to serve, remove the sides of the springform pan. Decorate with malted milk candies if desired. Slice and serve.