**Whisk.** In a heatproof bowl over a pan of barely simmering water, whisk yolks and sugar 5 minutes until pale and thick like ribbon. Remove from heat and cool 5 minutes.

**Mascarpone.** In a large bowl beat cold mascarpone with cookie butter 1 minute until smooth.

**Combine.** Fold cooled yolk mixture into the mascarpone.

**Whip.** Whip cold cream and vanilla to stiff peaks. Fold into mascarpone in 3 additions until no streaks remain.

**Dip.** Dip 15 biscoff cookies one at a time in espresso for 1 second per side. Layer in a 9x9 inch dish.

**Layer.** Spread half the mascarpone cream over the cookies. Repeat with remaining cookies and cream.

**Top.** Crush remaining 5 biscoff cookies and sprinkle on top. Drizzle with melted cookie butter. Chill 6 hours before serving.