Apple and Fig Custard

Name: Apple and Fig Custard
Ingredients: 4 tablespoons unsalted butter, plus more for dish; 2 tablespoons demerara sugar, plus more for sprinkling; 1/2 cup granulated sugar; 2 teaspoons finely grated lemon zest; 1 vanilla bean, halved lengthwise; 3 large eggs, room temperature; 2/3 cup whole milk, room temperature; 2 tablespoons apple brandy or dark rum; 3/4 cup crème fraîche, room temperature; 1/2 cup all-purpose flour; 1 teaspoon kosher salt, plus more; 2 pounds firm baking apples (about 4 large), peeled, cored, sliced into 1/2-inch-thick rings; 6 ounces fresh mission figs, halved lengthwise