In a bowl, combine the first six ingredients. Cut in butter until mixture resembles coarse crumbs. Whisk egg, milk and vanilla; stir into crumb mixture just until moistened. Spoon into a 9-in. x 5-in. loaf pan coated with cooking spray.
In a small saucepan, combine sugar and cornstarch; stir in water until smooth. Add raspberries and lemon juice. Bring to a boil; cook and stir for 1-2 minutes or until thickened. Pour over batter; cut through with a knife to swirl.
In a small bowl, combine flour and sugar. Cut in butter until crumbly. Sprinkle over batter; top with nuts. Bake at 350° for 35-40 minutes or until a toothpick inserted near the center comes out clean. Cool on a wire rack.