Preheat the oven to 325 F or 160 C and line a 9×9 inch square pan with parchment paper or grease with butter.

Beat together the butter, peanut butter and sugars until light and fluffy.

Add the egg and vanilla, continuing to beat.

Whisk in the salt and baking soda, followed by the flour.

Fold in the oats and chocolate chunks and set aside.

To prepare the cheesecake layer, whisk all the ingredients together until smooth.

Press about 2/3 of the cookie dough onto the baking pan in an even layer.

Pour the cheesecake mixture on top and and spread evenly.

Take bits of the remaining cookie dough and fatten in your hands, then place the flattened pieces on top of the cheesecake layer until it is covered as best as possible. You can also just crumble up the mixture and spread it on top.

Cover the pan with foil and bake for 20 minutes, uncover and bake for an additional 25-30 minutes- check until it no longer jiggles.