For the Oreo Cookie Crust:

1. Preheat oven to 350 degrees F.
2. Prepare an 8 inch by 8 inch baking pan, see note, and spray the inside with cooking spray.
3. Combine the Oreo cookie crumbs and the melted butter. Press into the bottom of baking pan.
4. Bake in 350 degree F oven for 8 minutes.
5. Heat raspberry jam in saucepan until starting to bubble and it becomes liquid.
6. Remove Oreo crust from oven and brush on warm the raspberry jam. Return to the oven and bake for 3 minutes until jam is set.
7. Reduce oven temperature to 325F.

For the Chocolate Cheesecake Filling:

1. Combine cream cheese, sugar, brown sugar, salt, and cocoa in the bowl of a stand mixer and beat with the paddle attachment until completely smooth, about 2 minutes. Scrape down bowl and paddle.
2. Add the eggs, one at a time, beating for 20 seconds after each addition. Scrape down bowl and paddle.
3. Add the cream and vanilla and mix until combined. Scrape down the bowl and paddle.
4. Add the melted, cooled chocolate and mix until combined.

To bake the cheesecake bars:

1. Pour the filling over the partially baked crust and bake at 325F until the sides are set and the middle is still wobbly, about 50 minutes. I like to bake it until the center reaches about 160 F. The cake will firm up as it cools. 
2. Remove the cheesecake from the oven and place the pan on a cooling rack. Run a knife along the sides of the pan (or between the cake and the foil if using) to help prevent cracking. Cool the cheesecake to room temperature, then refrigerate for at least 4 hours.
3. After the cheesecake has cooled, prepare the ganache. Pour the ganache over the top of the cheesecake (The ganache should be pourable, but not very warm.) and refrigerate for another hour.
4. Lift the cheesecake out of the pan. Cut into 16 squares, 2 inches by 2 inches each. For the neatest slices, wipe knife with a warm, wet cloth between each slice. Alternatively, rinse knife under warm water between each slice.

To decorate (optional):

1. Reserve some of the ganache for piping,
2. Using a piping bag and a star tip, pipe a rosette on the top of each bar. Top with a fresh raspberry

For the Raspberry Puree:

1. Thaw the raspberries and mix with sugar. Let macerate in bowl (or the blender) for 30 minutes.
2. Puree in blender until smooth.
3. Press through a fine mesh strainer using a rubber spatula to remove the seeds.
4. Add lemon juice and stir to combine.
5. This will make the 1/3 cup (113g) necessary for the ganache. Keep refrigerated until ready to use.

For the Chocolate Raspberry Ganache:

1. Finely chop the chocolate and put in a medium bowl.
2. In a saucepan, combine the cream and raspberry puree (or jam). Bring to a simmer over medium-high heat.
3. Pour the cream mixture over the chopped chocolate and let rest for 1 minute.
4. Whisk the cream mixture and melting chocolate until it is smooth and glossy.
5. Set aside at room temperature until needed.
6. If you will be reserving some ganache for piping, refrigerate it until it hardens enough to pipe.