Bring cherries, 1 cup sugar, cornstarch, and lemon juice to a boil in a medium saucepan, stirring constantly. Boil, stirring constantly, 1 minute. Remove from heat; stir in 3 tablespoons butter. Pour into a lightly greased 11- x 7-inch baking dish.
Combine remaining 1 cup sugar, flour, baking powder, and salt in a large mixing bowl. Add milk, 1/4 cup butter, and vanilla, and beat at medium speed with an electric mixer 2 minutes. Add egg, and beat 2 more minutes. Spoon batter evenly over cherry mixture.
Bake at 350° for 40 to 45 minutes or until golden, shielding with aluminum foil during the last 10 minutes to prevent excessive browning, if necessary. Cool in dish on a wire rack 15 to 20 minutes. Serve cobbler warm with ice cream.