Preheat the oven to 350°F. Line a 8x8-inch baking pan with parchment paper.
In a bowl, mix graham cracker crumbs and melted butter until evenly combined.
Press mixture firmly into the bottom of the prepared pan to form a crust. Bake for 5 minutes then remove from the oven and set aside.
In a separate bowl, whisk together mashed sweet potatoes, brown sugar, eggs, vanilla, cinnamon, ginger, and cloves.
Stir in the heavy cream until smooth and fully combined.
Pour the sweet potato mixture over the crust and spread evenly.
Bake for 35–40 minutes, or until the center is set and a toothpick comes out mostly clean.
Remove from the oven and sprinkle marshmallows evenly over the top.
Return to the oven and broil for 1–2 minutes, watching carefully, until marshmallows are golden and toasted.
Let cool completely before slicing into bars. Chill for cleanest cuts.