Preheat the oven to 325 F /162 C with the rack in the middle.  Line the bottom of a 9" round cheesecake pan or springform mold with parchment. Spray the parchment and sides of the pan.  Set aside.

Measure the cocoa, flour, salt and baking powder and sift them through a strainer.  Both the flour and especially the cocoa have a tendency lump.  The cocoa lumps don't want to dissolve in liquid but sifting will take care of that problem.

Beat the eggs and both sugars for about 3 minutes or until fluffy and lighter in color.

Add the oil and vanilla, mixing until completely combined.

Add the flour mixture and beat on low just to combine.

Pour into the pan, level the mixture and bake for 28 to 33 minutes until a tester comes out with a few moist crumbs clinging to it.

In a mixing bowl, beat the cream until stiff.  Remove the cream to another bowl.

In the same mixing bowl combine the peanut butter, cream cheese, powdered sugar and vanilla.  Beat until smooth on medium. 

Beat briefely until lighter in color.

Fold in the cream.

Pour onto the cake layer and spread evenly.

Chill overnight.

Combine the cream, corn syrup and butter in a small saucepan.  Heat until the butter melts but do not let it boil.  It should be steamy hot but not boiling.

Remove from the heat and submerge the chocolate.  Wait for 2 minutes the gently whisk until smooth.

Pour over the chilled cake and refrigerate until set.