Preheat oven to 350F. Line a 12 x 17 jelly roll pan with parchment paper and lightly spray with cooking spray.

In a large bowl, whisk together all Wet ingredients. In medium bowl sift together Dry Ingredients, then stir in chocolate chips. Add Dry to Wet ingredients and stir gently just until combined. Don’t overmix.

Spread batter into prepared pan and bake 20-25 minutes. Cool Pumpkin Bars completely before frosting.

Beat butter, sugar, cocoa powder and 2 Tbsp milk with handled mixer at medium-high speed until the mixture is smooth. Add cream cheese, 1 piece at a time, beating thoroughly after each addition. Add Nutella and vanilla and beat to combine. Add additional milk if needed to reach desired consistency.

Evenly spread frosting over cooled pumpkin bars. Garnish with mini chocolate chips, candy corns, etc. if desired (optional). Bars are best if frosting is allowed to set for at least 30 minutes. Store in an airtight container.