Put the tomatoes in a colander in the sink or over a bowl, and toss with 1-1/2 tsp. salt. Let drain for at least 45 minutes to release excess juice. Heat the oil in a 12-inch skillet over medium heat. Add the leeks, 1/4 tsp. salt, and 1/4 tsp. pepper; spread in an even layer, reduce the heat to low, and cook, covered, without stirring until the leeks begin to soften, about 5 minutes. Uncover and cook, stirring occasionally, until very tender, 10 to 15 minutes more. Transfer to a plate and let cool completely.
Meanwhile, position a rack in the center of the oven and heat the oven to 400°F. Let the dough sit at room temperature until pliable, 10 to 15 minutes.
In a small bowl, whisk the egg and cream.
Roll the dough between 2 sheets of lightly floured parchment paper into a 14-inch round, loosening the parchment from the dough occasionally and adding a bit more flour if it sticks. Transfer on the parchment to a baking sheet; remove and discard the top sheet of parchment.
Leaving a 2-inch border, sprinkle half of the cheese, half of the leeks, half of the tomatoes, 1 tsp. of the marjoram, 1/4 tsp. of the pepper, and a generous pinch flaky sea salt over the dough. Repeat with remaining ingredients.
Fold the edge of the dough up and over the filling. If the dough is sticking to the parchment, refrigerate it for 5 to 10 minutes, and then continue folding. Brush the folded dough with the egg wash. Bake, rotating the baking sheet once half-way through, until the crust is golden brown, 40 to 50 minutes. Let cool on a rack for 10 to 15 minutes. Serve warm or at room temperature.
nutrition information (per serving):
470, Fat Calories
31, Saturated Fat
16, Polyunsaturated Fat
2, Monounsaturated Fat
Photo: Scott Phillips