Preheat your oven to 350°F (180°C) and line a 9-inch pie pan with parchment paper, then set it aside for later.
In a large bowl, use a hand mixer to beat the softened butter, brown sugar, and sugar together until the mixture becomes light and fluffy.
2 sticks unsalted butter, ¾ cup brown sugar, ¼ cup sugar
Next, add the canned pumpkin puree, vanilla extract, and egg into the butter-sugar mixture. Beat again until everything is well combined. If you'd like to add orange food coloring, now is the time to mix in a few drops until you achieve the color you want.
½ cup canned pumpkin puree, 1 egg, 2 teaspoons vanilla extract, Orange food coloring
In a separate bowl, combine the flour, baking soda, salt, and cinnamon, stirring until they're evenly mixed. Gradually add this dry mixture to the wet ingredients, about ½ cup at a time, and continue mixing until you form a soft dough.
2 ¼ cups flour, 1 teaspoon baking soda, 1 teaspoon cinnamon, ½ teaspoon salt
Once the dough is ready, fold in the chocolate chips, mini marshmallows, and graham cracker bits. Use a silicone spoon to ensure everything is evenly distributed throughout the dough.
½ cup chocolate chips, ½ cup mini marshmallows, 6-7 graham crackers
Spread the dough evenly into the prepared pie pan. If you want to, you can top the dough with extra chocolate chips, marshmallows, and graham crackers for added texture and flavor.
Place the pan in the oven and bake for 20-25 minutes. You'll know it's done when the edges are golden brown and the marshmallows on top have a nice toasted look. Let the cookie cake cool in the pan for about 20 minutes, then lift it out using the parchment paper.
Slice it up and enjoy!