Preheat oven to 375ºF. Liberally spray a non-stick Bundt pan. Pour cajeta into pan, set aside. In a large bowl whisk together cake mix, water, melted butter and two eggs until well blended. Add sour cream and mix until well blended. Pour cake batter over cajeta. In a blender add evaporated milk, sweetened condensed milk, vanilla, pumpkin puree, pumpkin spice, 4 eggs and brown sugar; blend until smooth. Slowly pour flan mixture over cake batter. Cover with foil and place Bundt pan in a larger roasting pan. Add enough boiling water (between 6-8 cups) to reach halfway up the side of the Bundt pan. Bake for 1-1/2 hours or until a toothpick inserted comes out clean. Carefully remove from oven and allow to cool completely in pan. Once the pumpkin chocoflan has cooled completely, place in fridge to chill for 4 hours or overnight. To serve run a knife around side of pan to loosen edges. Invert onto cake stand or serving platter and garnish with pepitas.