For the cheesecake:

1. Preheat the oven to 200ºF / 95ºC.
2. Butter or spray a 8 inch round cake pan with 2 or 3 inch sides, and a non-stick surface. Or butter the pan and line the bottom with wax paper. The cake won't rise at all, but the batter will fill just below the 2-inch mark.
3. Put the cake pan in a larger  baking tray that will hold 1-inch of water.
4. In a large bowl beat cream cheese with an electric mixer for 1 or 2 minutes, until very smooth. There should be no lumps at all.
5. Gradually add the sugar, vanilla, rum and cognac and continue beating until perfectly smooth.
6. Add the eggs, one at a time, beating until each one is completely mixed before adding the next one.
7. Pour the mixture into the prepared pan.
8. Put the baking tray in the oven and, slowly, add very hot tap water up to 1-inch.
9. Bake for 8 hours. My oven has a 3 hour timer, so I had to check twice and set it again. Halfway through the baking the batter will start to appear a bit firmer, just barely.
10. After the 8 hours of baking, turn the oven off and carefully transfer the cake pan to a wire rack.
11. It will still be jiggly, like a flan. Let the cake stand there, untouched, until it cools completely.
12. Unmold onto the serving plate carefully, it is very soft.
13. Remember that you won't be able to move the cheesecake after you unmold it, so it will stay where it lands.
14. Cover with the roasted grapes and serve.
15. Or refrigerate for 4 hours or up to 3 days and serve. The texture will be firmer but still incredibly creamy. You can also freeze it, let it thaw in the fridge.

For the roasted grapes:

1. Preheat the oven to 350ºF / 180ºC.
2. Arrange grapes in a baking tray and roast for about an hour, until they are shriveled and sticky.
3. I left the clusters whole, but it's easier to separate the grapes before baking than
   after. Your choice.
4. Put the roasted grapes in a saucepan with the wine, and cook over medium heat for 5 minutes, until syrupy.