Preheat oven to 160 C or 325 F. Line your baking tray with parchment paper or grease with butter.

Melt the butter either in a saucepan or microwave. Keep aside. Don't do this too early as you still need it warm .

Stir together the flour and cornflour.

In a mixing bowl, beat / whisk together the egg, sugar, salt and vanilla. This takes around 3-5 minutes (at high speed) by electric beater and 10-12 minutes by hand . (My vanilla was clear)

When the mixture is pale , thick and fluffy, add in the melted butter and beat for a minute more until mixed well. The butter has sunk into the eggs here!

Fold in half the flour.

Fold in the other half of flour until you can't see flour anymore.

Its a thick sticky dough , still semi liquid. You could refrigerate it for upto half an hour to firm it up and make it easier to handle.

Line teaspoonfuls of the dough on your prepared tray , keeping around 2 inches space in between. These spread well! If you are finding it difficult to smoothen the dough mounds, wet your fingers with little water.

Bake in a preheated oven at 160 C for 18-20 minutes until edges are golden. Cool on the tray if you have lined it or transfer to a cooling rack if you have greased your tray. Once cool, transfer to an airtight container to maintain the crispiness or sandwich with fillings of your choice (I used ganache here) .