In a mixing bowl, whisk together the flour, tapioca, sugar, salt and vanilla extract. Pour in slowly the olive oil and combine with your hands until all of the dry mixture is incorporated and you make a ball of dough.

Preheat the oven to 350ºF/180ºC.

Line a baking pan with parchment paper and spread the dough, pressing it with your fingers in an even layer of approx. 0.2inch / 0.5 cm thick.

Cut with a cookie cutter or with a large upside-down glass.

Bake until it is just beginning to turn slightly golden around the edges (keep a close eye on it), about 15 to 20 minutes.

Remove from oven and let them cool for 30 minutes. Don´t remove them before they’re totally cooled, or they’ll crumble to bits.

Melt dark chocolate in a double boiler, or 45 seconds in the microwave, until smooth and shiny.

Dip half of the cooled cookies, one at a time, in chocolate.

Transfer back to parchment and let chocolate set completely before removing and serving. (you can use the refrigerator to speed this up)

Store the cookies in a cookie jar or a metal box.