In a large bowl, beat together the cream cheese and sugar until light and fluffy. Mix in eggs, sour cream, and vanilla until smooth. Pour the batter into the tart shell until the batter almost reaches the top. Do not over fill. Wrap the bottom of the tart pan in aluminum foil, then place on a baking sheet. Pour in enough water to cover the surface of the baking sheet. Place in the oven and bake for 10 minutes. Then reduce the heat to 300 degrees and continue baking for another 20 to 25 minutes.
Remove from the oven and allow to cool to room temperature, then transfer to the fridge to continue to chill. Meanwhile, in a small bowl, mix together the sour cream, sugar, and vanilla. Spread over the top of the cheesecake into a single, thin layer. Pile the cranberries and raspberries on top. Chill until ready to serve.