Beat 1 cup unsalted butter until smooth
Add 3 to 4 cups powdered sugar, 1 cup at a time
Mix in 2 to 3 tablespoons milk or cream
Add 1 teaspoon vanilla extract
Add a pinch of salt
Add yellow food coloring until pale gold
Add a tiny amount of brown or orange food coloring to deepen the gold tone
Mix in gold luster dust or edible gold powder for a metallic finish
Adjust with more powdered sugar if too thin
Adjust with more milk or cream if too thick
Use immediately or store covered until needed