Melt dark and white chocolates---separately---over a double boiler. When thoroughly dissolved, add heavy cream to white chocolate. Whisk, but if chocolate begins to lump, then place it back on top of the double boiler for a few seconds until it melts. Next, make cheesecake by beating the cream cheese until it is fluffy. Gradually, add sugar and vanilla. Beat in eggs---one at a time---and then blend in sour cream. Divide the mixture in half. To one half, add the dark chocolate, and to the other half add the white chocolate. Pour white chocolate later first into prepared pans, making sure to divide the mixture evenly. Pour the dark chocolate on top of the white, and avoid mixing the two together.
Bake at 350 degrees for 60 to 70 minutes, or until it feels firm. Turn oven off. Leave door slightly open, and allow to cool for 1 hour.
Converted by MC_Buster.