1. Start by making the dough. Put the flour in a large bowl. Add the salt to one side of the bowl and the yeast to the other side (if the salt makes direct contact with the yeast before it is diluted it can stop the yeast working). Pour over 160g of lukewarm water then combine to make a wet dough.
2. Tip onto a floured work surface and knead for 8-10 minutes. It will feel very sticky at first, but gradually you will notice the dough become smooth, silky and less sticky. Place the dough in a bowl, cover with cling film and leave somewhere warm (an airing cupboard is ideal) for 1 hour.
3. Meanwhile, prepare your toppings. Put the thyme, garlic and 1 tbsp of olive oil in a pestle and mortar together with a pinch of salt and bash vigorously until you have a green paste. Add the rest of the olive oil and stir through. Set aside until needed.
4. Preheat the oven to 250ºC and put two pizza stones or baking trays in the oven to heat up.
5. When the dough has had its hour, tip it onto a floured chopping board and divide in two. Using lots of flour to prevent sticking, press the dough into two thin circles using the flat of your hand to make each pizza as thin and even as possible.
6. Spoon the thyme oil onto the two pizza bases and spread it around right to the edges. Lay the mushrooms on top and finish with a scattering of parmesan. Take the pizzas, on their chopping board, to the oven then slide each pizza onto your pre-heated baking tray or stone. Cook for 10-12 minutes or until golden brown. Serve immediately.