Preheat your oven to 350°F. Grease a 9”x13” baking dish with neutral oil, butter or nonstick spray.
In a large mixing bowl, combine the two cans of pumpkin puree, evaporated milk, 1 cup of brown sugar (reserve ¼ cup for the oatmeal topping), eggs, pumpkin pie spice, cinnamon and vanilla extract. Mix until well combined.
30 ounces pumpkin puree, 12 ounces evaporated milk, 3 large eggs, 2 teaspoons pumpkin pie spice, 1 teaspoon ground cinnamon, 1 teaspoon vanilla extract, 1 ¼ cups light brown sugar
Pour the pumpkin mixture into the baking dish. Evenly sprinkle the dry spice cake mix over the top of the pumpkin layer. Add the pecans over the cake mix. Sprinkle the old-fashioned oats evenly over the pecans. Next, add the reserved ¼ cup of brown sugar evenly over the oats layer. Drizzle melted butter evenly over the entire top layer.
15.25 ounces yellow cake mix, 1 cup pecans, 1 cup old-fashioned oats, 1 cup unsalted butter
Bake in the preheated oven for 50 to 60 minutes, or until the top is golden brown and the edges are bubbling.
Once out of the oven, let the cake cool for about 15 minutes. If desired, drizzle caramel topping generously over the warm cake and serve with vanilla ice cream.