Finely crush the Biscoff or Speculoos cookies in the bowl of a food processor. You can also place the cookies in a resealable bag and crush them by rolling using a rolling pin.

In a large bowl, combine the cookie crumbs and drizzle them with the melted butter. Stir with a fork until the crumbs are evenly moistened.

In a large bowl, whisk the egg yolks until smooth.

To make the caramel/butterscotch mixture, In a small heavy saucepan stir together the sugar and 1/4 cup water. The sugar will look moist. Bring to a boil over medium heat and cook, without stirring, until the mixture begins to turn golden. Gently swirling the pan and continue to cook until sugar is amber like the color of honey. Don’t allow it to get too dark as sugar can quickly burn. Remove the pan from the heat as soon as the desired color is achieved. Off the heat, gradually stir in the heavy cream then set aside.

In a medium saucepan, whisk together the brown sugar, cornstarch, and salt. Gradually add the milk while whisking constantly. Stir in the vanilla bean paste and mix to combine. Cook over medium-high heat whisking frequently, until the mixture comes to a boil. Remove from heat and add in the caramel/butterscotch mixture.

Whisking constantly, slowly add about a quarter of the hot liquid mixture into the egg yolks. Make sure you whisk vigorously to prevent the eggs from scrambling. Add about another quarter of the hot liquid into the eggs while constantly whisking.

Now that the eggs are tempered, gradually pour the egg mixture back into the saucepan to combine it with the remaining hot liquid. Bring to a boil over medium heat whisking frequently and cook until the mixture thickens and reaches a pudding consistency, about 2-3 minutes.

Remove from the heat and stir in the butter while whisking vigorously for about a minute. This will help the pudding cool a bit before pouring it over the pie crust.

Pour the butterscotch pudding mixture into the pie crust. If your pudding has any lumps, pour it through a mesh sieve directly into the crust.

Cover with plastic wrap and chill in the refrigerator for 6 hours or overnight to allow the pie to set.

In a mixer fitted with the whisk attachment over medium-high speed, beat the heavy cream, vanilla paste and sugar until soft peaks form.

Spread the whipped cream over the chilled pie.

In a small mixing bowl, mix together the cookie crumbs and the finely chopped pecans. Sprinkle over the whipped cream topping.