1 cup (2 sticks) butter, softened, plus butter for pan
1/2 cup firmly packed brown sugar
1/2 cup chopped pecans
1 teaspoons ground cinnamon
2 cups sugar
3 large eggs
12 ounces sour cream
1 cup mashed cooked sweet potato (about 1 medium)
1 teaspoon vanilla extract
3 cups all-purpose flour
1 teaspoon baking powder
1 teaspoon ground cinnamon
1 teaspoon salt
1/4 teaspoon ground nutmeg
Rum Glaze, recipe follows
2 cups confectioners' sugar
1/2 cup heavy whipping cream
3/4 teaspoon rum extract
Pecans, for garnish