Lift the bread pan out of the machine and fit the blade. Put the egg in a jug and make it up to 150 ml (¼ pint) with water. Put the dough ingredients in the pan, following the order specified in the manual. Fit the pan into the machine and close the lid. Set to the dough programme. Check the dough after 5 minutes' kneading and add 1 tablespoon more water if it feels dry.
Prepare the topping. Heat 2 tablespoons oil in a frying pan and fry the onions for about 20 minutes, stirring frequently. Stir in the thyme and plenty of seasoning.
At the end of the programme turn the dough out on to a floured surface and roll it out thinly to a circle about 33 cm (13 inches) across. Lift it on to a large, greased baking sheet, reshape the circle and make a rim by folding over the edges of the dough and pressing them down firmly. Leave to stand, uncovered, for 10 minutes.
Bake in a preheated oven, 220°C (425°F), Gas Mark 7, for 5 minutes. Spread with the onion mixture in an even layer. Drain the can of anchovies, reserving the oil. Cut the anchovies into thin strips and use them to make a lattice pattern over the dough. Place the olives in the spaces between the anchovies. Drizzle with the anchovy oil and remaining olive oil.
Return the tart to the oven for 10–15 minutes until golden. Serve warm, scattered with extra thyme sprigs.