Place apples, cider, brown sugar, lemon juice, cinnamon, and nutmeg in a large dutch oven. Bring to a boil over high heat; reduce heat and simmer until apples are tender, about 25-30 minutes.
Remove from heat. Mash with potato masher to desired consistency.
Melt butter in a small saucepan over medium heat. Continue cooking until butter turns light golden brown.
Stir butter into applesauce. Season with salt to taste.
Let cool slightly then serve or place in an airtight container in the refrigerator for up to two weeks or the the freezer for up to a year.
