Line 14 inch deep dish pizza pan with nonstick foil.
Cream together butter and sugars.
Add eggs and vanilla.
Slowly mix in flour, graham cracker crumbs, salt and baking soda till well incorporated.
Stir in chunks or chocolate chips.
Spread dough into pan.
Bake 16-18 minutes until golden brown. (Do not underbake you want the base to be sturdy!)
Cool.
Melt milk chocolate and cream together in microwave until smooth.
Spread over crust, stopping about ½ inch from the edge.
Pop in freezer 10 minutes to firm chocolate.
Sprinkle mini marshmallows over chocolate in a single layer.
Broil about 6 inches from the element for 2-3 minutes until lightly toasted. Watch carefully!
Cool.
To slice, run a knife under very hot water, then dry to slice. I also sliced mine while cookie cake was still a bit warm from broiler which helped.