Combine powdered sugar and 2 Tablespoons of milk and whisk together.
Add additional milk, a splash at a time, until glaze is smooth and the glaze falls in a smooth ribbon from the whisk.
For a thicker/sturdier glaze or one that you would like to drizzle in lines that hold their shape, the ribbon that falls from the whisk should hold its shape for several seconds before dissolving back into the bowl. For a thinner glaze it should dissolve into the bowl within one second.
Whisk in vanilla extract.
Use to drizzle over muffins, scones, coffee cakes, etc.
I very rarely sift my sugar when making a glaze. I’m typically able to whisk any lumps out. However, if your powdered sugar seems particularly lumpy or a perfectly smooth glaze is critical, I recommend sifting after measuring to guarantee smooth results.
I recommend using whole milk. You may substitute heavy cream, a lower fat milk, or non-dairy milk. Keep in mind that if you are using a lower-fat milk, it will be thinner and you will likely need slightly less than is called for.
If you accidentally made your glaze too thin, simply whisk in more powdered sugar, a Tablespoon at a time. If your glaze is too thick even after adding all of the milk, add more milk a teaspoon at a time until desired consistency is reached.