Creating these Gooey Pumpkin Marshmallow Bars is a straightforward process. Follow these steps to ensure that your bars turn out perfectly every time:

Prepare the Crust:

1. Preheat the Oven: Start by preheating your oven to 350°F (175°C). This ensures that your bars bake evenly.
2. Mix the Crust Ingredients: In a medium-sized bowl, combine the graham cracker crumbs, melted butter, and granulated sugar. Mix until the crumbs are well-coated and resemble wet sand.
3. Form the Crust: Press the crumb mixture evenly into the bottom of a 9×13-inch baking dish. Use the back of a spoon or a flat-bottomed glass to press down firmly, creating an even layer.
4. Bake the Crust: Place the crust in the preheated oven and bake for 8-10 minutes until it’s lightly golden. Remove from the oven and let it cool slightly while you prepare the pumpkin layer.

Prepare the Pumpkin Layer:

5. Mix the Pumpkin Ingredients: In a large mixing bowl, combine the canned pumpkin puree, granulated sugar, brown sugar, eggs, and vanilla extract. Beat together until smooth.
6. Add the Spices: Sprinkle in the ground cinnamon, nutmeg, ginger, cloves, and salt. Mix until all the spices are evenly incorporated.
7. Spread the Pumpkin Layer: Pour the pumpkin mixture over the cooled crust, spreading it evenly with a spatula.

Prepare the Marshmallow Layer:

8. Add the Marshmallows: Sprinkle the mini marshmallows evenly over the top of the pumpkin layer.
9. Bake the Bars: Return the baking dish to the oven and bake for 25-30 minutes, or until the marshmallows are golden brown and the pumpkin layer is set.

Finish with Topping:

10. Optional Toppings: If using, sprinkle chopped pecans and chocolate chips over the top of the bars immediately after removing them from the oven.
11. Cool and Slice: Allow the bars to cool completely in the pan before slicing them into squares. This will help the layers set and make them easier to serve.