1 box yellow cake mix (or white)
1/2 cup canola or vegetable oil
1/2 cup milk or buttermilk
1 box (3.4 oz) Vanilla Instant Pudding Mix
1/2 cup sour cream
15 oz can pumpkin puree
1 stick (8 tablespoons) butter
3/4 cup packed light brown sugar
1/2 tsp. ground cinnamon
3/4 cup powdered sugar
1/4-1/2 cup heavy cream or milk (start with 1/4 cup and add a little more if needed)
1. Preheat oven to 350℉ and spray a jelly roll pan with non-stick cooking spray.
2. Place cake mix, eggs, oil, milk, pudding, sour cream and pumpkin into a stand or electric mixer, beating until well combined, about 1-1/2 minutes. Pour into prepared pan, spreading evenly.
3. Place butter into a microwave safe bowl and melt, about 30-40 seconds. Add brown sugar and cinnamon to bowl and mix until combined. Drizzle mixture evenly over cake. Then take a knife and run it through to swirl.
4. Bake cake for 30-35 minutes, until cooked through and remove. In a bowl add powdered sugar and cream or milk and mix until creamy and smooth. Drizzle over warm cake. Let cool for 20 minutes before cutting into squares. Refrigerate if not serving same day.