Glazed lemon shortbread biscuits

Put the sugar in a bowl, add the lemon zest and rub them together to infuse; this releases the oil and adds flavour.

Variation: use orange zest or lime zest instead.

Add the butter to the sugar and zest and mix at speed 6 until the sugar is completely incorporated into the butter, then scrape down.

Mix in the vanilla paste.

Crack in one egg and mix until it is thoroughly blended into the butter.

Sift the dry ingredients onto parchment paper and add them to the mix. Run at speed 2 so the flour does not fly, then speed 4 for about a minute until it comes together; do not overmix and do not let it get too soft.

Knead the dough -- it should not be sticky -- and rest it in the fridge about 10 minutes to make it easier to work.

Cut off part of the dough and roll it into a log about one inch thick, then cut it into even pieces.

Roll each piece into a ball, place them on a lined baking tray about two inches apart so they do not stick together while baking, and flatten them down slightly.

Bake 10 to 12 minutes at 340F, between 170C.

Mix the icing sugar with fresh lemon juice, thinning with more juice if it is too thick.

Dip each cookie in the glaze and knock off the excess.

These are ice box cookies: the dough can be made ahead and frozen, then thawed in the fridge before rolling and shaping.

Cut the candied lemon into little cubes and place one in the centre of each cookie, then leave them to set.

Variation for candied zest: zest the lemon, bring it to a boil with sugar and water, strain, spread the zest on a baking tray, sprinkle sugar over it and leave it to set hard.