Vanilla Bean Buttercream Frosting

From 6 Bittersweets
Very slightly adapted from Cupcake Project

1 1/2 C powdered sugar (add more until it reaches your preferred consistency)
1/2 C unsalted butter (room temperature)
1/4 teaspoon salt
2 teaspoons vanilla bean paste (add more to taste)
[I used seeds from 1 whole vanilla bean plus 1/2 teaspoon pure vanilla extract]
1 tablespoon milk

Mix together sugar and butter until they are blended and creamy. Add vanilla bean paste [or pulp plus pure extract], salt, and milk and continue to beat for another minute. If desired, add more vanilla bean paste to taste, or more powdered sugar to make it stiffer.