01 -
Whisk together all-purpose flour, eggs, milk, water, melted butter, vanilla extract, and salt until completely smooth. Cover and chill for at least 30 minutes.
02 -
Heat a nonstick pan over medium-low. Pour a thin layer of batter, swirling to coat the base evenly. Cook until edges lift and underside is lightly golden, then flip and cook briefly. Transfer each crêpe to a cool plate. Repeat until all batter is used.
03 -
In a bowl, beat together speculoos cookie butter, vanilla extract, and powdered sugar until smooth. In a separate bowl, whip the heavy cream to soft peaks. Gently fold the whipped cream into the speculoos mixture until evenly combined. If desired, fold in mascarpone or cream cheese for added richness.
04 -
Place one cooled crêpe on a serving plate. Spread 2–3 tablespoons of filling evenly over the crêpe. Top with another crêpe and repeat, layering crêpes and filling until all are used, finishing with a crêpe on top.
05 -
Cover the assembled cake and refrigerate for at least 2 hours to allow flavors to meld and for easier slicing.
06 -
Before serving, spread warmed cookie butter over the top layer and scatter with crushed speculoos cookies if desired. Slice with a sharp knife and serve chilled.