Mathilde's Tomato Tart

Name: Mathilde's Tomato Tart
Cook time: 2 h
Total time: 2 h
Cuisine: European, British
Ingredients: 1 3/4 cups (230 grams) all-purpose flour; 1/2 teaspoon granulated sugar; 1/2 teaspoon coarse or kosher salt; 1/2 cup (4 ounces or 115 grams), cold unsalted butter, cut into 1-inch pieces; 1 large egg; 1 tablespoon water; 3 large very ripe tomatoes, heirloom or other, sliced crosswise 1/4-inch thick (about 1.5 pounds); Coarse or kosher salt; 1 small garlic clove; 1 cup (15 grams) basil leaves, loosely packed; 2 cups (25 grams) parsley leaves, loosely packed; 2 tablespoons (30 ml) olive oil, plus more for brushing; 1 tablespoon smooth Dijon mustard (double if it you like mustard; skip if you don’t); 2 ounces (55 grams) hard cheese, thinly sliced or coarsely grated (see Note); Freshly ground black pepper