Step 1Bring the heavy cream, milk, vanilla bean and seeds just to a boil in a medium saucepan over low heat.
Step 2In a bowl, whisk the sugar and eggs. Slowly whisk in some of the cream-milk mixture into the eggs, then pour in remaining cream and whisk until combined. Strain through a fine mesh strainer. Cool.
Step 1Heat the oven to 300 degrees. In a saucepan over medium heat, bring 4 cups water, the sugar, cinnamon, star anise and vanilla beans and seeds to a simmer. Cook 5 minutes.
Step 2Cut off the top third of each apple (making little "caps") and set aside. Cut a thin slice off the bottom of each apple -- just enough so that there's a flat surface and the apples are level. Using a melon baller, evenly hollow out each apple, leaving a half-inch wall around and going almost to the bottom without making any holes.
Step 3Place the apples (the tops and hollowed apples) in a 3-inch-deep baking pan. Put 1 tablespoon of the spice syrup into each apple and pour the remaining around the apples. Cover the pan with aluminum foil and bake until tender, 15 to 20 minutes.
Step 4Remove the foil. Remove the apple tops from the baking pan and reserve. Pour out the liquid inside each apple. Pour the custard into the apples, filling to the brim
Step 5Bake until the custard is set, 45 minutes to 1 hour. Remove the custard-filled apples from the poaching liquid and cool. Refrigerate until cold.
Step 6To assemble, heat the broiler. Sprinkle 1 teaspoon superfine sugar on top of each apple. Place on a baking sheet and put under the broiler to caramelize the sugar, 1 to 2 minutes. Or use a butane torch. Watch carefully so as not to burn the sugar. Place each apple on a dessert plate and serve immediately with the apple top leaning on the apple.