In small saucepan, heat raspberries with 1 T sugar until boiling.

In small bowl, mix 1/2 T cornstarch with 1/2 T water. Add to hot mixture, stirring quickly to avoid lumps. Set aside to cool.

In small saucepan, melt 4 T butter. Add 2 T sugar and the graham cracker crumbs. Mix thoroughly and then press into the bottom of a greased 8" springform pan.

In mixing bowl, combine cream cheese and sugar, stirring until smooth. Add eggs one at a time, mixing gently with each addition.

In small bowl, mix 1/2 T cornstarch with 1/2 T water. Add to cream cheese mixture and stir.

Divide batter in half. Add the cooled raspberry mixture to one half; add 1/2 T vanilla and 1/2 c sour cream to second half.

Pour 1/2 of vanilla batter into prepared pan, covering the crust. Carefully spread the raspberry batter on top, using a ladle or wide spoon. Finish by carefully spreading the rest of the vanilla batter on top.

Bake at 350 degrees for 30 minutes. Move temperature down to 325 degrees, cover loosely with foil, and bake 45 minutes longer.

After your cheesecake is finished baking, turn off oven, open the oven door, and allow to cool in oven for 15 minutes before removing to cooling rack. Chill at least 4 hours before serving.