Oreo Cheesecake

Beginning of June was my son' s birthday. One of his favourite cake is this Oreo Cheesecake. He said he wanted oreo cookies at the bottom and top as well. So here it is. This cake can be kept quite well, for up till 2 weeks if there is any left.
Ingredients:
500g Philadelphia cream cheese
140g sugar
75g sour cream
45g cream
3 eggs
1 tsp vanilla extract
12 pieces of Oreo cookies
Extra 6 pieces of Oreo cookies crushed real fine to sprinkle on top.
8 inch round cake pan, Roasting pan for water

To make base:
1. Brush the inside of an 8 inch cake pan for a 1kg cake with a little butter.
2. Crush 12 (double) pieces cookies, discard cream filling. (Put biscuits in plastic bag and  crush it with a rolling pin)
3. Melt 50g butter and mix into biscuits.
4. Put mixed cookies onto the cake pan and press it flat with a spoon.
5. Put it in the fridge to harden and set.
Method
1. Pre-heat your oven to 180 deg C.
2. In a mixing bowl, beat the cream cheese and sugar until smooth for at least eight minutes at medium speed.
3. Add sour cream and cream to the mixture and continue to beat till smooth.
4. Add the eggs one at a time, beating after every addition. Then add the vanilla essence. Continue to mix at the medium speed till the mixture becomes fluffy.
5. Pour it into the cake pan with the prepared base and bake in a bain marie (a large roasting pan of barely simmering water in which the cake pan, or a container with the pan in it, is placed, and the water level 1/3 up the sides of the cake pan), which allows the mixture to be heated gently and evenly for 45 minutes to one hour at 180 deg C.
6. Be careful: Over-baking your cheesecake will cause the skin to crack and it will become dry and difficult to cut.
7. Let the cheesecake cool down to room temperature.
8. Store it in the fridge.
9. When it is cold, put the crushed cookies in a small sieve and sift it on top of the cheesecake.
9. Serve cold.