Pillsbury has an easy recipe for blackberry cobbler. Ree Drummond of the Food Network also has a recipe for blackberry cobbler that uses either fresh or frozen blackberries.
To make the Pillsbury blackberry cobbler, whisk 1 cup of sugar with 1 egg and 1 cup of all-purpose flour until the mixture has the texture of coarse crumbs. Place 4 cups of frozen blackberries in a lightly greased 8-inch square glass baking dish, drizzle with 1 tablespoon of lemon juice and sprinkle the sugar, egg and flour mixture on top. Drizzle 6 tablespoons of melted butter over it and bake for 40 to 45 minutes in a preheated 375 F oven. Serve with vanilla ice cream if desired. This recipe makes 6 servings and takes one hour and five minutes from start to finish.
To make Ree Drummond's version of blackberry cobbler, mix 1 cup of self-rising flour with 1 cup of sugar and 1 cup of whole milk. Whisk in 1/2 stick of melted butter. Rinse 2 cups of fresh or frozen blackberries, pat them dry, pour the batter into a 3 quart baking dish that has been greased with butter and sprinkle the blackberries evenly on top. Sprinkle 1/4 cup of sugar over the berries and bake in a preheated 350 F oven for 50 minutes. Sprinkle 2 tablespoons of sugar over the berries and bake for 10 additional minutes or until the cobbler is golden brown and bubbly.