Sweet Potato Casserole

• 5 medium sweet potatoes cooked, peeled, and mashed
• 1/3 cup milk
• 3 tbs light brown sugar
• 2 tbs sugar
• 2 tbs butter, melted
• 1/2 tsp salt
• 1/2 tsp ground cinnamon
• 1/4 tsp ground nutmeg
• 1/4 tsp ground ginger
• 1 cup mini marshmallows