Measure 200ml (7 floz) of hot but not boiling water from the kettle into a heat proof jug and top up to 400ml with cold water. Stir in the dried yeast with the sugar and leave for 5 minutes for the yeast to activate, then stir in the olive oil. The yeast is ready when the top has developed thick foam.

Sieve the flour into a large warm bowl and stir in the salt. Make a well in the centre and pour in the warm, yeasty liquid.

Work the mixture together using a large spatula or your hands until it leaves the sides of the bowl and forms dough. The dough should be slightly wet, but not sticky - if it seems a little dry, add a little more water.

Turn the dough out onto a lightly floured work surface; knead for 5 - 6 minutes until it has become smooth and elastic. Return the dough to the bowl, cover with some oiled cling film and set to rise in a warm place until doubled in size. This will take around 40 - 60 minutes depending on the warmth of the rising place.

Turn the risen dough out onto a freshly floured work surface and knock out the air created during the first rising by kneading 3 - 4 times.

Roll out the dough, using a little more flour to stop the dough from sticking, into a rectangle 48 cm (19 inch) x 25 cm (10 inch). Spread the surface with the tomato paste followed by the pesto, leaving a 2cm (¾ inch) gap along both long sides of the dough. Scatter over the wilted spinach leaves, followed the grated mozzarella and ¾ of the grated cheddar cheese.

Grease the Le Creuset Cast Iron Roaster with butter and dust the surface with 2 - 3 tablespoons of the semolina or polenta. Place the dough rolls cut side up into the roaster, forming 4 rows of 3 rolls each, leaving an equal amount of space around each one. Cover the roaster with a sheet of lightly oiled clingfilm and leave to rise in a warm place for 30 - 40 minutes or until doubled in size. To aid the rising process, warm the roaster first by placing it into a low heat oven for a few minutes.

Preheat the oven 15 minutes before the end of the second rising to 200°C / Fan 180°C / 400°F / Gas Mark 6.

Remove the clingfilm from the rolls, sprinkle over the remaining grated cheese, and place the roaster on a central rack in the oven. Bake for 35 - 40 minutes.

Cook's Notes

Semolina is coarse grain flour made from Durum wheat.

To wilt the washed spinach, place the leaves into a large sauce pan with a very small amount of water, put on the lid and steam over a low heat for a few minutes. Alternatively, place the washed spinach into a glass bowl cover with cling film and microwave for 1 - 2 minutes. The leaves need to lose their volume but not be cooked through, drain any liquid from the spinach and discard it.

For a variation, add some chopped cooked bacon or ham to the filling.