Pre-heat oven to 375°F. Line a baking sheet with parchment paper and set aside.
In a large bowl add 1/2 cup ricotta, 1 cup fontina, 1 egg yolk, 5 cracks black pepper and a generous pinch of kosher salt. Mix until well incorporated and no streaks of egg can be seen. Thinly slice 1 heirloom tomato into 5-6 pieces, transfer to a piece of paper towel and season with salt and more black pepper.
Transfer 1 sheet puff pastry to the lined baking sheet and trace a 2 inch border with fork, then using the prongs, poke several small holes on the inside of the border. Using a spatula, spread out an even layer of the cheese mixture over the poked pastry. Top with your salted tomato slices and a drizzle with olive oil. Gently fold the edged towards the centre, pinching where needed to seal everything together.
In a small bowl, beat the remaining egg, then coat the border of the pastry and top with sesame seeds. Bake for 40-45 minutes, or until the pastry is golden brown and flaky. Remove and let cool before topping with fresh tarragon and a drizzle of hot honey.
