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