#1 Preheat the oven to 400 degrees F #2 Place 2 pieces of puff pastry onto a silicone-lined baking sheet. Press the short seam of 1 piece onto the other to form the rectangular base of the tart. Cut seams off the other 2 pieces of puff pastry and press them into the edges of the base to act as the border #3 Freeze dough until firm, about 10 minutes #4 Score border with a knife, making shallow cuts 1/4-inch apart. Press the bottom of a fork onto the seam in the middle and poke holes all over the base #5 Bake tart shell until lightly golden and partially puffed, about 10 minutes. Press down on the base using the bottom of a fork. Avoid pressing border. Let cool for 10 minutes #6 Spread mustard over the inside of the tart. Arrange tomato slices into a single layer on top and cut a few slices in half to fill in the gaps. Season with salt and pepper. Generously sprinkle herbes de Provence on top. Add Parmigiano-Reggiano cheese and drizzle most of the olive oil on top #7Bake in the preheated oven until pastry is well browned and crispy, 25 to 30 minutes. Cool to room temperature on the baking sheet or transfer to a wire rack using 2 spatulas. Drizzle remaining olive oil over the tart and sprinkle fresh oregano, parsley, and thyme on top