THE FILLING:

Mix softened cream cheese and sugar until very smooth and light in texture. Add the eggs, one at a time, mixing well with each. Add in the vanilla. Divide into three batches, about 2-1/2 cups each. In a double boiler, melt the white chocolate with 1/4 cup of the heavy cream and stir until smooth. Add to one of the batter thirds and mix thoroughly. Next, melt the milk chocolate with 1/4 cup of the heavy cream (you can use the same double boiler, if you work from light to dark) and add it to one of the batter portions and mix well. Do the same with the 60% cacao bittersweet chips. Cover and let set in the refrigerator for at least two hours.

THE CRUST:

Reduce the cookies to crumbs in a food processor. Add the melted butter and pulse a few times to mix. Spray a non-stick spray onto the sides of a 9 x 3 spring form pan. Pour in the crumb mixture and press onto the bottom of the pan. Bake at 350 degrees F for 6 minutes until set. Remove from the oven and reduce the temperature to 320 degrees F.Carefully layer the cheesecake flavors on top of one another, working from darkest to lightest, smoothing each layer so that the strata are as even and distinct as possible. Bake at 320 degrees F for at least 1-1/2 hours, or until the edges are set, but the middle will be jiggly. Turn off the oven and leave the cheesecake to finish baking for another hour, until the middle is nearly completely set. You may need to cover the top with a piece of foil to prevent the white chocolate layer from over browning. Remove from the oven and let cool thoroughly in the refrigerator for at least 4 hours.

THE GANACHE TOPPING:

Combine the chocolate and heavy cream in a double boiler until very smooth. Stir in the vanilla. Add additional heavy cream until the ganache is the proper spreading consistency. You may simply top the cheesecake with the ganache, or you may "frost" the whole thing for a very polished look.