1. To make the biscuits,put the olive oil in a small container and freeze for at least one hour. Preheat the oven to 150C and roast the almonds for 10-12 minutes or until they take on some colour,then leave to cool.

2. Transfer almonds to a food processor and process until finely chopped. Add the flour,icing sugar,salt and zest,then process for another minute until fully combined. Remove the olive oil from the freezer – it won't be quite frozen – and add to the food processor together with the vanilla extract. Pulse until the mixture comes together,then form a ball with the dough and wrap loosely in cling film. Press to flatten into a disc and chill in the fridge for 30 minutes.

3. Preheat the oven to 170C. Line a baking tray with baking paper. Roll the dough into balls about the size of a ping-pong ball. Spread out on the lined tray and bake for 16-18 minutes;the underside of the biscuits should be firm and a light golden brown.

4. Remove biscuits from oven and allow to rest for 3 minutes on the tray. Sift the extra icing sugar into a bowl,then one at a time,gently roll the warm biscuits in the icing sugar. Return them to the still-hot tray and allow the icing sugar to set into a thin coating.

Serving suggestion: These biscuits go well alongside mysangria granita.