In a bowl, mix the wholemeal flour with all the other ingredients up to and including the salt. Add the butter and rub together using your hands to form an even, crumbly mixture. Add the egg, mix quickly to form a soft dough – do not knead. Cover the dough and chill for approx. 1 hr. Roll out the dough between two sheets of baking paper to a thickness of approx. 4 mm. Cut out 20 circles (each approx. 8 cm in diameter), transfer to a baking tray lined with baking paper. Place one slice of tomato on each.
Approx. 20 mins. in the centre of an oven preheated to 200°C, slide the tray onto the top shelf and bake for a further 7 mins. Remove and allow to cool slightly. Sprinkle with basil and fleur de sel.