Preheat the oven to 425°F (220°C) and line a sheet pan with parchment paper.

Roll out the puff pastry on a cutting board and slice it into 9 even rectangles, leaving a quarter-inch border.

In a bowl, whisk together ricotta, Parmigiano-Reggiano, kosher salt, black pepper, minced basil, garlic powder, and oregano until smooth and well combined.

Place the puff pastry rectangles on the prepared baking sheet, spacing them about an inch apart. Spoon approximately 1½ tablespoons of the cheese mixture into the center of each rectangle.

Top each tartlet with halved mini heirloom tomatoes, brush with olive oil, and then brush the edges of the pastry with the egg wash.

Bake in the preheated oven for 20 minutes, or until the pastry is golden brown, rotating halfway through for even cooking.

Once baked, remove from the oven and let cool on a wire rack. Just before serving, sprinkle with fresh basil, flaky sea salt, and a dash of freshly ground pepper.