Use pure pumpkin puree, not pumpkin pie filling. Use room temperature eggs for better texture. Don’t overmix the batter to keep bars tender. Swirl Nutella gently for distinct ribbons. Start checking baking time early to avoid overbaking. Cool completely before slicing. Variations include adding nuts, using different spreads, making vegan, topping with frosting, adjusting spices, or baking mini bars. Store leftovers airtight at room temperature for 3 days, refrigerate up to a week, or freeze up to 3 months.