Crunchy tea biscuits with corn flour

Difficulty:  Time: INGREDIENTS (x 6 persons): 250 g white non-raising plain flour 120 g corn flour (for Polenta*) 230 g unsalted butter 140 g powdered sugar 1 egg + 1 yolk 1 (unwaxed) biologic lemon Fine salt Vanilla-flavoured powdered sugar (optional) for decoration WHAT TO DO: 1. Preheat the oven to 180C/350F/Gas 4. Line a baking tray with ...