Mix together the flour, parmesan and vegetable powder in a large bowl. Sprinkle bits of butter over dough and using your fingers start mixing and rubbing until you have used all the butter and the mixture resembles fine breadcrumbs. In a small bowl, mix the yogurt, lemon juice and water and add this to the butter-flour mixture. Use your hands again to mix. Gather the lumps into a slightly flattened ball. If needed add a bit more flour until the dough is not too sticky. Wrap in a large piece of parchment paper, and chill in the fridge for 45 minutes.

While the dough is resting, preheat the oven to 180°C and prepare the filling. In a bowl mix together all ingredients for the ricotta filling.

Grease two 35,5 x 11,5cm tart tins with greasing spray or butter. Take the dough out of the fridge, place it on the parchment paper, put one more piece of parchment paper on top and roll out flat to a long piece. Cut it in half and place in the tins. With your finger-tips press the dough to cover the bottom and sides of each tin. The dough should be about ½ cm thick. With a spoon, add the ricotta filling and top with the tomatoes. Add just a little olive oil and salt and bake in the oven for about 45 mins.