*Bake your cake layers.
Slowly bring first 4 ingredients to a boil in a medium-sized saucepan, stirring occasionally.
Set saucepan off burner & add vanilla. Slowly stir in powdered sugar. Beat vigorously, cover & let this set while layers are cooling. Most of the time I use an electric mixer unless I sift my powdered sugar. I leave it on the stove but not on the burner I cooked it on. I highly recommend sifting the powdered sugar (measure then sift).
*IMPORTANT: Ice the cake once the layers are cooled but the icing is still warm but not hot. Slowly add more milk (a little at the time) if the icing is too stiff. This icing sets up quickly. I like for it to drizzle down the sides of cake.
NOTE: Very good on yellow, chocolate or spice cake layers. I made chocolate layers from Amy's homemade chocolate cake. What an excellent recipe......Homemade Chocolate Cake