Preheat oven to 350°F.
Combine brown sugar, water, butter and salt in a saucepan. Bring to a boil over medium heat; reduce heat and simmer 5 minutes. Remove from heat; stir in vanilla and rum extracts. Set aside.
Combine flour, sugar, baking powder, cinnamon and salt in a large mixing bowl. Mix well. Combine milk, melted butter, and vanilla in a small bowl. Add liquid ingredients to the flour mixture; blend quickly.
Spread cake batter in a greased 13×9-inch cake pan. Pour sauce over top. DO NOT mix. Sprinkle pecans over the liquid.
Bake for 20 to 25 minutes or until the center bubbles up. Serve warm. Top with ice cream or whipped cream, if desired.