Preheat the Oven: Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking pan to prevent sticking.
Mix the Wet Ingredients: In a large bowl, combine melted butter and brown sugar, mixing until smooth. Then, add pumpkin puree, eggs, and vanilla extract. Stir until the mixture is well-combined.
Combine the Dry Ingredients: In a separate bowl, whisk together all-purpose flour, baking powder, baking soda, cinnamon, nutmeg, and salt.
Merge Wet and Dry Ingredients: Gradually add the dry ingredients to the wet mixture, stirring until just combined—resist the urge to overmix!
Layer the Batter: Pour half of the batter into the prepared pan, smoothing it out evenly. Drizzle half of the caramel sauce over this first layer.
Add Remaining Batter and Caramel: Pour the remaining batter on top of the caramel layer. Drizzle the rest of the caramel sauce over the surface, using a knife to gently swirl it into the batter.
Bake: Place the pan in the oven and bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.
Cool and Cut: Allow your blondies to cool completely before cutting them into squares. Serve them warm or at room temperature, and enjoy!