Instructions Make sure you read my cooking tips before you start. Step 1 - Two hours before, slice the tomatoes and lay the slices on a cutting board. Salt them on both sides and lay them flat on a cooling rack. They will loose some of their juice so the crust doesn’t get too soggy when baking. Pre-heat your oven to 425F (220C) with a rack in the middle. Butter and flour a 9 or 10 inch tart pan/pie dish. Unroll the puff pastry sheet and fit it into a pan. If needed, cut the excess that hangs from the edges. Poke the dough all over with a fork.Step 2 -Evenly spread the Dijon Mustard over the bottom. Sprinkle 1 1/2 cup (150g) of grated cheese on top. Optional: Sprinkle 2 tablespoons of bread crumbs – they will absorb the juice from the tomatoes. Step 3 - Arrange the tomato slices in the pastry crust in an overlapping pattern and in an even layer. Sprinkle with a pinch of salt and Herbs de Provence. Repeat the process until no tomato slices remain; you should be able to have three layers of tomato slices. Sprinkle again with a pinch of salt, black pepper, Herbs de Provence and the remaining 1/2 cup (50g) of grated cheese. Bake for 35-40 minutes, until the crust looks crisp and golden. Enjoy warm or cool.