Step 1
Preheat oven to 325 degrees F (165 degrees C).
Step 2
Toss pumpkin cubes olive oil and 1 teaspoon salt together in a bowl; spread onto a baking sheet.
Step 3
Roast pumpkin in preheated oven for 30 minutes increase heat to 425 degrees F (220 degrees C) and continue roasting until the pumpkin is tender about 30 minutes more.
Step 4
Cool pumpkin cubes completely. Trim away outer edges so you have only soft mashable pumpkin remaining. Measure 2 cups of mashed pumpkin; reserve remainder for another use.
Step 5
Preheat oven to 350 degrees F (175 degrees C). Prepare a 9x13-inch baking dish with cooking spray.
Step 6
Mash 2 cups pumpkin sour cream and creme de cacao together in a bowl with a potato masher until the mixture is relatively lump-free.
Step 7
Beat butter and sugar together in a large bowl with an electric mixer until light and fluffy; add eggs one at a time thoroughly beating each egg into the butter mixture before adding the next. Beat vanilla extract and the pumpkin mixture into the butter mixture with the last egg.
Step 8
Mix flour pumpkin pie spice baking soda baking powder and 1/4 teaspoon salt together in a separate bowl; stir into the pumpkin mixture. Fold chocolate chips through the resulting batter and pour into the prepared baking dish.
Step 9
Bake in the preheated oven until a toothpick inserted into the center comes out clean about 50 minutes.