Masterclass focaccia

Pre-heat the oven to 200C/180C Fan/Gas 6. Line 2 baking trays with baking paper. Sift the flour and salt into a large bowl. Add the yeast and stir to mix.

Add 4 tbsp of the olive oil and 300ml tepid water. (Make sure the water is tepid – it shouldn’t feel hot to the touch.) Mix together to form a soft dough.

Turn the dough out onto a floured surface. Knead by folding the dough in half, then pushing it firmly away from you with the heel of your hand. Fold over again, turn it slightly on the board and repeat. Do this for 10-15 minutes until the dough is stretchy, smooth and elastic. See tip below.

Wash and dry the bowl, then grease it generously with olive oil. Put the dough back in the bowl and turn until it is coated in oil. Cover the bowl with greased cling film. Leave in a warm place until the dough has doubled in size – about 45 minutes in a warm room, or longer in a cooler place.

While the dough is rising, put the onions in a pan with 2 tbsp olive oil and toss to coat. Put a round of baking paper on top of the onions, then put a lid on the pan. Cook over a very low heat for 10-15 minutes until soft but not golden. Tip into a bowl and leave to cool. Put the risen dough on a floured surface and press firmly to knock the air out. Fold it and flatten again.

Sprinkle the thyme on top and knead into the dough until evenly distributed. Cut the dough in half and shape each piece into a rectangle about 30cm x 20cm. Place on the lined baking trays.

With your finger, press the dough surface to make dimples, then scatter the onion over the top. Cover loosely with some greased cling film and leave to rise to about twice the size.

Bake for 30-35 minutes until golden. Remove from the oven, drizzle over the remaining 2 tbsp olive oil and sprinkle on the sea salt.

Tips: You have to use strong bread flour, not ordinary flour, because it has a higher gluten content; this makes the dough stretchy when you knead it, for a bread that rises well and has a lovely light texture. When you're kneading the dough, it will be rather sticky at first before becoming smooth and elastic. You can also knead bread dough in some food mixers or processors. While it's almost impossible to over-knead dough by hand, it can happen with a machine so check the manufacturer's instructions.