How to Make It
In a food processor, pulse the flour with the 1/2 teaspoon of sugar and the salt until combined. Add the vegetable shortening and pulse 5 or 6 times, until the mixture resembles small peas. Add the cold butter and pulse 5 or 6 times, until the mixture resembles peas. Add the ice water and pulse 5 or 6 times, just until the pastry is evenly moistened.
Transfer the pastry to a lightly floured surface and knead just until it comes together. Flatten the pastry into a 6-inch disk, wrap in plastic and refrigerate until firm, at least 30 minutes.
Preheat the oven to 375°. In a large bowl, toss the blackberries with the remaining 1 1/4 cups of sugar, the lemon juice, nutmeg and 1/3 cup of flour. Let stand at room temperature, stirring gently once or twice, until slightly juicy, about 15 minutes. Fold in the melted butter. Transfer the fruit to a round 2-quart glass or ceramic baking dish.
On a lightly floured surface, roll the pastry out to a 1/4-inch thickness that is slightly larger than the baking dish. Drape the pastry over the berries. Trim the overhang to 1/2 inch and fold it under itself, pressing the pastry onto the rim of the dish. Crimp the edge decoratively and make 3 slashes in the center of the pastry.
Bake the cobbler for 1 hour, or until the filling is bubbling and the pastry is golden. Cover the edges with foil if the crust browns too quickly. Let cool for 20 minutes before serving.
Vanilla ice cream.