In a small bowl, mix together the powdered sugar and lemon juice. If you need to thin it out more, add more lemon juice ½ tablespoon at a time.
Notes
There are several ways to easily adjust this powdered sugar lemon glaze, including:
Salt: A pinch of salt will enhance the flavors and balance the sweetness in the lemon cake glaze. All you need is a pinch.
Vegan butter: Add a teaspoon of melted unsalted (or salted) plant-based butter to the lemon icing glaze for a silky mouthfeel and richer flavor.
Strawberry lemon glaze: Either blend and strain strawberries OR combine sliced strawberries and sugar in a small bowl and allow it to macerate. You can then use the juice extracted from the fruit instead of some of the lemon juice in the icing.
Lemon and raspberry drizzle: Use the same method as above, but with raspberries.
Lemon elderflower glaze: Use a teaspoon or so (adjust to taste) of elderflower cordial in place of some lemon juice.
Ginger lemon drizzle icing: Add a small amount of the syrup from a jar of stem ginger in place of some lemon juice.