Begin by preheating your oven to 400°F (200°C). In a large bowl, combine 3 cups of all-purpose flour with 6 tablespoons of chilled butter and 3 ounces of chilled vegetable shortening, both cut into cubes. Using your fingertips, rub the fats into the flour until the mixture resembles fine bread crumbs.
Gradually mix in approximately 3–4 tablespoons of cold water until a soft, pliable dough forms. Wrap the dough in plastic wrap and refrigerate for about 30 minutes to allow it to rest and firm up, which will guarantee a flakier final product.
Divide the chilled dough into 4 equal pieces. Roll out each piece on a lightly floured surface and cut into a 7-inch round. Place one peeled and cored tart apple in the center of each round and gather the dough around it to form a dumpling, sealing the edges.
Reserve any dough trimmings and cut them into decorative leaf shapes. Attach these leaves to the tops of the dumplings using a small amount of water as adhesive, then pierce a small hole in the top of each dumpling to allow steam to escape during baking.
Lightly brush each dumpling with milk to create a golden glaze, then place them on a greased baking sheet.
Bake for 35–40 minutes until the pastry is golden brown and the apples inside are tender when pierced with a fork. Before filling the apples, mix together ¼ cup brown sugar and ½ teaspoon ground cinnamon, then spoon this mixture into the cored center of each apple for added sweetness and warmth.
Serve the dumplings hot, ideally with custard or vanilla ice cream on the side.
