In a medium bowl, whisk pumpkin puree, eggs, granulated sugar, brown sugar, pumpkin pie spice, and 1 t cinnamon until smooth.

Stir in evaporated milk.

Spray a 4–6 qt crockpot with non-stick spray and pour in the pumpkin mixture.

In another bowl, whisk cake mix with remaining 1 t cinnamon. Stir in melted butter until crumbly.

Sprinkle cake mixture evenly over pumpkin mixture in the crockpot.

Cook on “Low” for 4 hrs or “High” for 2 hrs. If using, add pecans halfway through. (I set a timer for the half-way mark or I tend to forget them.)

Serve warm with ice cream or whipped cream.