Rustic Plum Galette with Flaky Homemade Crust

Ingredients

• 1½ cups all-purpose flour, spooned into measuring cup and leveled-off
• ½ teaspoon salt
• 2 tablespoons granulated sugar
• 1½ sticks (12 tablespoons) very cold unsalted butter, cut into ½-inch pieces
• ¼ cup very cold water
• ½ cup sliced almonds
• 1 lb plums (3 to 4, depending on size)
• 2 tablespoons all-purpose flour
• ¼ cup plus ⅓ cup granulated sugar
• 1 egg, beaten
• 1 tablespoon turbinado or coarse sugar
• 2 tablespoons apricot jam, best quality (optional)