Preheat oven to 400 degrees. Generously butter a 13-x-9-x-2-inch baking dish; set aside.

In a large bowl, combine blueberries, blackberries, sugar, lemon juice, and vanilla. Toss to coat.

In a separate bowl, combine flour, cornstarch, and salt. Combine flour mixture with fruit mixture, stirring well. Pour mixture into prepared baking dish. Top with Sweet Biscuits.

Bake for 30 minutes. Cover with foil and continue baking for 30 minutes. Allow cobbler to cool for at least 10 minutes before serving. Serve with Old-Fashioned Vanilla Ice Cream, if desired.

In a large bowl, sift together flour sugar, baking powder, baking soda, and salt. Using a pastry blender, cut in butter until mixture resembles coarse meal. Make a well in the center of mixture. Add buttermilk and vanilla. Using a fork, stir until a dough forms.

Turn dough out onto a lightly floured surface. Using hands, gently knead 3 or 4 turns. Pat dough to 3/4-inch thickness. Using a 3-inch star cutter, cut biscuits, using dough scraps only once. Use as a topping for cobbler.

Editor's Note: Sweet Biscuits also make a great foundation for shortcake. Simply place on parchment-lined baking sheets and bake at 450 degrees until light golden brown, usually 12 to 15 minutes.

In a large saucepan, combine half-and-half, sugar, reserved vanilla seeds, and vanilla extract. Cook over medium-high heat until mixture just begins to boil. Remove from heat and set aside.

In a large bowl, whisk egg yolks until smooth. Using a ladle, pour 1 cup hot vanilla mixture in a slow steady stream into yolks, whisking constantly. In the same manner, add 3 cups hot mixture, 1 cup at a time. Add egg mixture to saucepan, whisking well.

Cook over medium-high heat, stirring constantly, until thick enough to coat the back of a wooden spoon or until temperature reaches 170 degrees on an instant-read thermometer, being careful not to let it boil.

Pour custard into a fine-mesh sieve* and strain into a stainless-steel bowl set in an ice-water bath. Let cool to room temperature, stirring often. Cover custard well with plastic wrap or transfer to an airtight container. Refrigerate for 2 hours, stirring occasionally to prevent a skin from forming on custard.

Pour custard into the container of a 4-quart ice-cream freezer. Freeze according to manufacturer's instructions.

*If you do not have a fine-mesh sieve, cheesecloth works just fine.