Preheat your oven to 400°F. Line a baking sheet with foil and place the sweet potatoes on top. Use a fork to pierce the sweet potatoes a few times. Bake for about 40-45 minutes until soft and the skins start to wrinkle. Let them cool slightly.

Reduce the oven temperature to 350°F. As the sweet potatoes cool, whisk together the sugar, butter, milk, vanilla, and salt in a bowl.

Peel the cooled sweet potatoes and add them to the mixture. Mash everything together until smooth. Beat in the eggs until fully mixed.

Spread the mashed sweet potato mixture into a small baking dish. Bake for 20 minutes at 350°F.

Scatter the mini marshmallows over the top and return to the oven. Bake for 5-10 minutes until the marshmallows are toasted and golden. Serve warm.