Make the mashed potato. Peel the maris piper and cut into 2.5 cm pieces. Boil in salted boiling water until tender, about 10 minutes. Drain and mash with a potato masher until smooth. Set aside to cool and measure out the desired quantity.
In a large bowl mix together the flour, salt, sugar and yeast.
Make a well in the centre and add the olive oil and warm water. Using a spatula mix the dry and wet ingredients together.
Add the mashed potato and fold through the dough, making sure it is evenly dispersed. Smear the dough around the bowl to make sure it is evenly incorporated.
Shape the dough into a bowl and then cover with some cling film and leave the dough to rise in a warm place for about 30 minutes, or until it doubles in volume.
Transfer the dough to a large oiled bowl and fold the edges of the dough into the centre 6-8 times. Tuck the folds into the middle and flip the dough over to shape it into a ball. Cover the bowl again with cling film and leave to rise in a warm place for another 30 minutes, until doubled in size.
Make the confit garlic: place the garlic cloves in a small saucepan covered with olive oil on medium heat. Once the oil becomes hot, turn the heat down to low and leave for 10 minutes. The garlic should not sizzle. Drain, keeping the oil in a glass jar to use in other dishes, and set the garlic aside.
Cut the cherry tomatoes in half and set aside.
Prepare a 26 x 20 x 5cm pan with 2 tbsp of olive oil, smeared across the base and along the sides of the pan. You can also line it with some parchement if you’re worried about it sticking. Make sure to smear olive oil on top of the parchment.
Put the dough into the pan and stretch and pull the dough to fill out the base as best as you can to get a roughly even surface. Cover the pan with cling film and leave in a warm place for 40 minutes until it expands and fills the pan and rises.
Smear the surface of the dough with olive oil by drizzling over about 2-3 tsp of oil and rubbing it lightly with your hands. Then using both your hands, push your fingers into the dough to leave indents. Do this about 6-7 times.
Press the confit garlic and cherry tomatoes onto the surface of the dough. Pick and press the thyme and/or rosemary into the rough evenly across the surface. Then sprinkle over some sea salt.
Bake for 25-30 minutes until the top is golden and crisp.
Turn the dough out onto a cooling rack and let it rest for 10-15 minutes before serving. It is best enjoyed fresh and warm!
The dough will keep for 3 days in a sealed zip lock bag. Reheat small portions of the dough in the oven to get it extra crisp and warm!