Blend the speculoos cookies into a powder. Pour into a mixing bowl and mix with the melted butter.
Spread the speculoos paste over the bottom of a high-sided baking pan and press it down to create an even layer.
Mix together the fromage blanc, cream cheese, heavy cream, lemon zest strips, and natural lemon flavoring. Add the sugar and eggs, then beat the mixture until combined.
Pour the mixture over the speculoos crust. Bake for 55 minutes at 180 °C.
Let it cool outside the oven, then refrigerate it until the next day.
