Preheat oven to 350 degrees.

Using a food processor, crush the oreos until crumbled. Add in melted butter and pulse until the mixture is like wet sand. Alternatively, brush the oreos in a large ziploc bag using a rolling pin or a meat mallet. Combine with melted butter.

Press crumb mixture into the bottom and up the sides of a 9 inch springform pan. Bake at 350 for 10 minutes. Set aside to cool.

Using a microwave, melted chocolate chips in 30 second bursts, stirring in between until melted. Set aside to cool.

In the bowl of a stand mixer (or using a hand-held mixer) beat the cream cheese until soft and fluffy. Add in the sugar and cocoa powder, and mix well. Beat in the eggs, one and a time, mixing until just blended. Mix in melted chocolate and mix until just combined.

Pour batter into baked crust.

Wrap pan in a double layer of foil. (Alternatively, place springform pan in a larger, 10-inch cake pan.) Set wrapped pan inside a large roasting pan and fill with enough hot water to come up about an inch on the side of the springform pan.

Bake at 350 degrees for 45 minutes. Turn oven off and and crack the oven door open, using a wooden spoon handle to leave the door cracked. Let cheesecake set in oven for one hour.

Remove from oven to cool completely on wire rack.

To make ganache, bring cream and butter to a simmer and pour over chopped chocolate. Allow to sit for 2-3 minutes and stir until smooth. Pour over cooled cheesecake.

Refrigerate for at least two hours or overnight before serving.

To serve, run a knife around the edge of the springform pan before loosening the sides and removing. Slice with thin knife that has been run under hot water.