Ingredients
For the Sour Dough Starter:

Marriage’s Finest Strong White Flour
Water
Fresh yeast – broken into small pieces

For the filling:

250 g Wild Suffolk Ceps – sliced
350g Peak Hill Farm Organic Onions –sliced
30ml Laurel Farm Thymus Marjorie
8.5 ml Olive Oil
Malden Sea Salt

Sour dough starter

100g Sour dough starter
455g Marriage’s Finest Strong White Flour
280g Water
10g Fresh Yeast – broken into small pieces
8.5ml Malden Sea Salt – finely powdered

Sour Dough Starter:

This is not a purist, wild yeast starter, but one based on commercial baker’s yeast. It doesn’t quite have the complexity of flavours provided by the wild yeasts, but it does bring certain desirable qualities and can be made to work in a bread machine.

Put 400g of white bread flour, 400g cold water and 2.5ml fresh baker’s yeast in a bowl and whisk to a lump-free batter.  Pour into a plastic container and fit the lid leaving a small gap for gases to escape.  Set aside in a cool place for three days, then store in the fridge.

Before using the starter, remove it from the fridge and allow it to warm to room temperature.  Then whisk vigorously before measuring out.

To refresh or replenish the starter, add 220g white bread flour and 200g cold water.  Whisk the mixture and leave to stand in a cool place for 1 day before storing once again in the fridge.  Refresh once per week.

The flavour will develop as the culture ages.

Prepare the filling:

Put 30ml of olive oil in a heavy based frying pan.  Add the sliced onions and put over a low heat.  Fry the onions slowly, moving them regularly to avoid burning or sticking.  Continue until the onions are caramelised, then transfer them to a plate to cool.

Prepare the loaf:

Pre-heat the oven to 250˚C, inserting a baking stone if you have one.

Put the dough ingredients in a 4l mixing bowl.  Combine the ingredients using your fingers or a bread scraper, then turn out onto a clean work surface.  Do not sprinkle the surface with flour.

Work the dough using the French method, until the dough is smooth, silky and elastic, about 15 to 20 minutes.

Return the dough to the mixing bowl, cover and rest for 45 minutes.

Lay a large sheet of baking paper on a work surface and sprinkle generously with flour.

Using the dough scraper, gently transfer the dough to floured paper and press out to an approximate square of even thickness.  Cover and rest for a further 15 minutes.

Using your finger tips, dimple the left hand two thirds of the dough.  This portion will form the base.

Using a rolling pin, roll out the right hand. Using a sharp knife, make some cuts in the rolled-out portion of the dough.  This portion will be folded across the base to form a lid.

Brush the base portion with olive oil, and then layer it with slices of mushroom and onion.  Sprinkle with thyme leaves and a little salt.

To close the loaf, slide a baking sheet under the lid portion, then lift it and move it over the base portion, such that the lid rolls over the base.  Carefully separate the paper from the lid.

Trim any ragged edges from the dough, and then trim off the excess baking paper.

Using a baking sheet transfer the loaf to the oven, spray water into the bottom of the oven and close the door.  Try to minimise the time that the oven door is open.  Reduce the temperature immediately to 230˚C and bake for 12 minutes.

Open the oven door to release the steam and then close it and bake for a further 4 minutes.

Remove from the oven and cool on a wire rack.

Note:  Details of the French method of working dough can be found in a number of books including dough by Richard Bertinet..