Easy Bourbon Sweet Potatoes

3  20 ounce cans vacuum-packed sweet potatoes
3/4 cup sugar
1/3 cup bourbon or preferred brown liquor, like dark rum
1/2 cup butter
1/2 teaspoon vanilla
Miniature marshmallows

Melt butter and mash together with remaining ingredients. Put in heatproof casserole and heat through. Place marshmallow on top and bake in 350-degree oven for about 30 minutes until marshmallows are brown and potatoes are heated through. To make ahead: Chill prepared but baked potatoes overnight to allow flavors to meld. Remove from refrigerator at least 30 minutes before baking and top with marshmallows. Serves 8.