For the pastry, grate the frozen butter into the flour. Add the parmesan and thyme, season, and toss with your fingers until the butter is coated. Add the water and bring it together to form a dough. Do not knead, you want flecks of butter in here. Pat into a disc, wrap in baking paper and chill for 30 minutes.

Meanwhile, toss the tomatoes with the oil, thyme and a good pinch of salt.

Roll the pastry on a sheet of baking paper to a rough 32cm round, about 8mm thick. Slide the paper onto a tray and chill for 20 minutes while you mix the filling.

Preheat the oven to 200°C (180°C fan-forced). Mash the feta with the brine, lemon zest and a grind of pepper then the spekboom (or rocket or watercress). Spread it from the centre of the pastry, leaving a 4cm border. Dust with the flour (this keeps the base from going soggy). Arrange over the tomatoes. Make angled cuts every 10cm or so then fold the border up and over the filling, pleating so it holds. Brush the pastry with egg and finish with salt flakes and plenty of black pepper.

Bake for 50 minutes, until the crust is deep golden and the tomatoes have blistered. Cool for 10 minutes. Scatter with extra spekboom (optional) and serve with the lemon wedges.