Preheat your oven to 350°F (175°C). Crush 32 Biscoff cookies into fine crumbs and mix with 6 tablespoons of melted unsalted butter until combined. Press into a 9-inch pie dish and bake for 10-12 minutes; allow to cool completely.

In a medium saucepan, combine the granulated sugar and water over medium heat, stirring until dissolved and golden, about 5-7 minutes. Stir in ¼ cup of heavy cream until smooth.

In another saucepan, whisk brown sugar, cornstarch, and salt. Gradually blend in whole milk and bring to a boil, stirring constantly until thickened.

Whisk 6 egg yolks in a bowl. Gradually pour in the hot milk mixture while whisking to temper. Return to heat for 2-3 minutes until thickened, then remove from heat and stir in 1 tablespoon of unsalted butter.

Cover pie with plastic wrap and refrigerate for at least 6 hours or overnight to set.

Beat heavy whipping cream in a bowl until soft peaks form, then add powdered sugar and vanilla bean paste, beating until stiff peaks form.

Spread whipped cream over the chilled pie and optionally sprinkle with pecans or crushed cookies before serving.