Brown Sugar Sauce recipe.

Ingredients
2 tablespoons butter
2 tablespoons all-purpose flour
1/4 teaspoon salt
1/2 cup packed brown sugar
1 cup boiling water
1 teaspoon vanilla extract

Directions
In a medium saucepan, melt butter or margarine. Add flour and salt; stir until smooth.
Stir in brown sugar. Blend thoroughly and cook over medium heat, stirring constantly, until mixture bubbles and is lightly browned, about 5 minutes. Remove from heat.
Stir in boiling water. Return to heat and bring to a boil, stirring constantly, until smooth and thickened. Add vanilla extract and stir until well blended. Serve hot.