Put a small pot of water on the stove. Once it comes to a boil add the honey and sugar, stir until they dissolve.
Transfer the syrup to a ceramic bowl to allow it to cool faster. In the meantime, you can prepare the other things.
Smear a tray with a little butter and sprinkle with a little flour. Cut the walnuts using a walnut chopper. Sift the flour with the baking soda and vanillas.
Add the walnuts and sifted flour mixture to the cooled syrup, stir well with a spoon. Pour the mixture into a square 8 3/4″ (22 cm) tray. Distribute the marmalade on top after cutting it to pieces with a spoon.
Bake in a preheated 392°F (200 °C) oven for 20 min. with the fan on.
Once baked, take the cake out onto a platter and sprinkle powdered sugar through a lace napkin over it. Cut it into squares or rectangular pieces.