01 - 
                Place the peeled and cubed sweet potatoes in a large pot, cover with cold water, and bring to a boil over high heat. Cook until fork-tender, about 15 minutes.
              
              
              
                02 - 
                Drain the cooked sweet potatoes thoroughly and transfer to a large mixing bowl. Mash until smooth and lump-free.
              
              
              
                03 - 
                Add brown sugar, unsalted butter, milk, and vanilla extract to the mashed potatoes. Stir until the mixture is fully combined and creamy.
              
              
              
                04 - 
                Lightly grease a baking dish and spread the sweet potato mixture evenly. Sprinkle mini marshmallows over the surface as desired.
              
              
              
                05 - 
                Bake in a preheated oven at 350°F (175°C) for 25 to 30 minutes, or until the center is heated through and marshmallows are golden brown.