In a large saucepan, cook raspberries and water over medium heat for 5 minutes. Add lemon juice. Combine sugar and cornstarch; stir into fruit mixture. Bring to a boil; cook and stir for 2 minutes or until thickened. Cool.
In a large bowl, combine the flour, sugar, baking powder and baking soda. Cut in butter until mixture resembles coarse crumbs. Stir in eggs, sour cream and vanilla (batter will be stiff).
Spread half into a greased 13-in. x 9-in. baking dish. Spread raspberry filling over batter; spoon remaining batter over filling. Combine topping ingredients; sprinkle over top.
Bake at 350° for 40-45 minutes or until golden brown. Combine the glaze ingredients; drizzle over warm cake. Yield: 12-16 servings.
Notes
For a half batch, try only using 1 cup raspberries, 1/4 cup water, 1/2 tbsp lemon juice, 1/3 cup sugar, 2 tbsp corn starch. Also for a half batch, use the full recipe for the icing.