Easy Caramel Icing (Reserved)

1/2 cup light brown sugar
1/2 stick butter or margarine
1/4 cup evaporated milk
1/2 cup powdered sugar
1 teaspoon vanilla 

Optional garnish
Pecan halves

Add brown sugar, butter and milk to a small saucepan and bring to a boil; cook for three (3) minutes, stirring frequently and watching closely so it does not burn. 

Pour the hot mixture over the powdered sugar and vanilla. Beat rapidly and drizzle over the cake. 

If desired, sprinkle with pecan halves.

Or this?
3/4 cup light brown sugar
3/4 cup butter (12 Tbsp = 1.5 sticks)
6 Tbsp evaporated milk (= 3/8 cup)
3.5 cups powdered sugar
1.5 teaspoons vanilla 

In a small saucepan over Low heat, heat butter and brown sugar, stirring constantly until sugar melts.

Blend in evaporated milk; cool.

Gradually beat in sugar until of spreading consistency. Stir in vanilla.