
4 pounds sweet potatoes, scrubbed
Nonstick cooking spray
1 cup granulated sugar
⅓ cup 2% reduced-fat milk
¼ cup salted butter, softened
2 large eggs
1 teaspoon vanilla extract
¼ cup pecan pieces
¼ cup packed dark brown sugar
2 tablespoons all-purpose flour
1 tablespoon salted butter, melted