For filling:Whisk together sugar and cornstarch in a large saucepan. Stir in water and lemon juice, then raspberries. Cook and stir over medium heat. Boil for 2 minutes, stirring constantly. Set aside.

For topping: Combine flour and sugar in a small bowl. Cut in butter with a pastry blender of fork until crumbly; stir in the nuts.

While filling cools, spray a 9" spingform pan with cooking spray. Preheat your oven to 325°.

For batter: Combine flour, sugar, baking powder, soda, and salt in a large mixing bowl. Cut in butter with a pastry blender or fork.

Combine eggs, sour cream, and almond extract in a small bowl; whisk until smooth. Stir into dry ingredients. Batter will be very thick.

Spread half of batter in the bottom of the prepared springform pan. (I pat mine into the pan with wet hands.)

Pour raspberry filling over the batter; spread with a spoon. Take remaining batter flatten with your palms. Arrange over the filling. It's fine if there are gaps.

Sprinkle crumb topping over the top of the coffee cake.

Bake in a preheated 325° oven for about 40-45 minutes, or until a toothpick inserted in the center comes out with moist crumbs.

Let cool in the pan for 10-20 minutes, then run a plastic knife around the edge. Remove the sides of the pan.

Serve warm or at room temperature.