Cottage Cheese Tomato Tart

0 Heat the oven to 400°F with a rack in the center position.
1 Unfold the puff pastry onto a sheet of floured parchment paper. Dust the top with more flour. Using a rolling pin, flatten the creases and roll to about an 14x9-inch rectangle. Using a sharp knife, lightly score a 1-inch border around the edge, taking care not to cut all the way through the pastry. Prick the center all over with a fork. Transfer the pastry, still on the parchment, onto a baking sheet.
2 Brush the border with the beaten egg. Sprinkle the border with the Parmesan, followed by the sesame seeds. Bake, pushing down the center with a fork halfway through if it puffs up, until lightly golden-brown, about 15 minutes. If the pastry has puffed up, gently press down with a spoon to deflate.
3 Meanwhile, prepare the tomatoes and filling. Line a baking sheet or cutting board with a double layer of paper towels. Arrange the tomatoes in a single layer and sprinkle with the salt. Let sit for 10 minutes to draw out excess moisture. Pat the tomatoes dry with paper towels.
4 Whip the cottage cheese and Boursin together in a standard or mini food processor until smooth. If you don’t have a food processor, whisk the two cheeses together in a mixing bowl until smooth and creamy. Dollop over the puff pastry and spread into a thin, even layer. Season with freshly ground black pepper. Arrange the tomato slices evenly over top and sprinkle with salt and more black pepper.
5 Bake until the edges are puffed and the bottom is crisp and deeply golden-brown, 15 to 20 minutes. Drizzle with pesto. Serve warm or at room temperature.