Start by placing 1 cup of softened butter in a large mixing bowl. Using an electric mixer, beat the butter on medium speed for about 2-3 minutes until it’s light and fluffy.

Gradually add 4 cups of powdered sugar to the beaten butter, one cup at a time. Mix on low speed until combined, then increase to medium speed. Incorporate 2 teaspoons of lemon extract and 2 tablespoons of lemon juice, mixing for another 1-2 minutes until smooth.

Slowly add ½ cup of sweetened condensed milk to the butter mixture, one tablespoon at a time. Continue to mix on medium speed for about 2-3 minutes until the frosting is light and airy.

If the buttercream is too thick, gradually mix in an additional teaspoon of lemon juice until reaching desired consistency. If too runny, add more powdered sugar by the tablespoon as needed.

For an extra zing, stir in finely grated lemon zest from one lemon. Mix just until combined for a beautifully zesty finish.

Use the frosting immediately to frost cooled cakes or cookies, spreading generously or piping onto treats as desired.