In a large mixing bowl, whisk together the flour, eggs, milk, and melted butter until smooth. Heat a non-stick skillet over medium heat and add a little butter to coat. Pour a small ladle of batter into the pan, swirling to create a thin layer. Cook for 1-2 minutes until edges lift, then flip and cook for another minute. Continue this until all batter is used, stacking crêpes to cool.

In a separate bowl, pour in the heavy cream and add the powdered sugar and vanilla extract. Using an electric mixer, whip the cream on medium-high speed until soft peaks form, about 3-5 minutes. If using cream cheese, first beat it smooth, then fold in whipped cream until fully combined.

Warm the Speculoos spread in a microwave-safe bowl for about 15-20 seconds until slightly warm and fluid. Stir well to ensure smoothness for easier spreading.

Place one crêpe on a serving plate. Spread a thin layer of vanilla cream, followed by a dollop of Speculoos spread. Add another crêpe and repeat the layering process until all crêpes are stacked.

Cover the crêpe cake loosely with plastic wrap or aluminum foil and refrigerate for at least 4 hours, preferably overnight, to allow flavors to meld and layers to set.

Dust powdered sugar generously over the top using a fine sieve. Sprinkle crushed Speculoos cookies for added texture, then slice and serve chilled.