In a medium saucepan, melt butter over medium-high heat. Add brown sugar and milk, and bring to a boil. Boil for exactly 2 minutes, stirring constantly. Remove from heat, and add confectioners’ sugar and vanilla extract, whisking to combine.
Use immediately.
Recipe by TeaTime Magazine at https://teatimemagazine.com/pumpkin-chai-bundt-cake-recipe/