Combine the butter, granulated sugar, and honey in a heatproof bowl set over a saucepan of gently simmering water. Stir until melted and smooth.

Stir in the baking soda and watch as the mixture foams and becomes lighter. Remove it from the heat and let it cool for several minutes.

Gradually whisk in the lightly beaten eggs, then add the flour in portions. Mix just until a soft, slightly sticky dough forms, taking care not to add substantially more flour than needed.

Divide the warm dough into 8 to 10 equal portions. Roll each portion very thinly into an 8- or 9-inch circle between parchment sheets or on a lightly floured surface, trimming if desired and reserving the scraps.

Bake the layers one at a time at 350°F (175°C) for approximately 4 to 7 minutes each, until puffed and lightly golden. Bake the trimmed scraps as well, and watch closely because thin layers brown quickly.

Whip the cold heavy cream with the powdered sugar until thick. Fold in the sour cream and vanilla, or briefly mix everything together until smooth and spreadable.

Place one cake layer on a serving plate and spread it with a thin, even layer of cream. Continue stacking and filling until all layers are used, then cover the top and sides with the remaining cream.

Crush the baked scraps into fine crumbs and press them over the top and sides of the cake. Refrigerate for at least 8 hours, preferably overnight, before slicing.