First melt 1/2 stick of butter in a small saucepan on medium heat, make sure not to burn the butter.
Then add roughly 1/3 cup of chocolate chips, stir with a whisk until melted careful not to burn the chocolate chips.
Remove the pan from the burner and add 1/4 of milk and 1 tsp of vanilla extract.
Also add 1 cup of powdered sugar to this mixture and stir until all lumps are gone.
Let cool for about 1 - 2 minutes and then pour over vanilla ice cream or whichever flavor you choose.