2
Toss pumpkin cubes, olive oil, and 1 teaspoon salt together in a bowl; spread onto a baking sheet.
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.
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.
5
Preheat oven to 350 degrees F (175 degrees C). Prepare a 9x13-inch baking dish with cooking spray.
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.
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.
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.
9
Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 50 minutes.