Preheat your oven to 350°F (175°C). Line a muffin tin with 12 cupcake liners.

In a large bowl, combine the yellow cake mix, canned sweet potato puree, cinnamon, and nutmeg. Mix with a hand mixer (or a stand mixer) until well combined.

Step 2: Make the Graham Cracker Crust

In a separate large bowl, combine the crushed graham crackers, melted butter, sugar, and salt. Stir until the crumbs are evenly moistened.

Step 3: Assemble the Cupcakes

Press about 1 tablespoon of the graham cracker mixture into the bottom of each cupcake liner, creating a thin crust.

Scoop the sweet potato cupcake batter on top of the crusts, filling each liner about 3/4 full.

Step 4: Bake the Cupcakes

Bake for approximately 22 minutes, or until the cupcakes are golden brown and a toothpick inserted into the center of a cupcake comes out clean.

Step 5: Cool the Cupcakes

Let the cupcakes cool in the muffin tin for a few minutes before transferring them to a wire rack to cool completely.

Step 6: Make the Marshmallow Frosting

While the cupcakes are cooling, make the frosting. In a large bowl, beat together the softened butter and marshmallow crème until smooth and combined.

Gradually add the powdered sugar, beating until the frosting is smooth.

Add the vanilla extract and salt, and beat until well combined.

Step 7: Frost and Garnish

Transfer the frosting to a piping bag fitted with a large closed star tip (or your preferred tip). Pipe the frosting onto the cooled cupcakes.

Garnish with chopped toasted pecans and a sprinkle of cinnamon sugar.

Serve and enjoy these delicious and festive Sweet Potato Pie Cupcakes!