01 - Combine dried lavender buds and boiling water in a small bowl. Steep for 10 minutes, then strain and discard the buds. Allow the lavender-infused liquid to cool completely.
02 - In a large mixing bowl, beat softened butter on medium-high speed for about 3 minutes until smooth, creamy, and pale in color.
03 - Gradually add powdered sugar to the creamed butter, 1 cup at a time, mixing on low speed and scraping down sides as needed until fully incorporated.
04 - Pour in 2 teaspoons of cooled lavender infusion, vanilla extract, and heavy cream or milk. Beat the mixture on medium-high for 2 to 3 minutes until the frosting is light and fluffy.
05 - Add a drop of purple food coloring, if desired, and mix until an even pastel color is achieved.
06 - Spread or pipe the buttercream immediately onto fully cooled cakes or cupcakes. Garnish with edible flowers, if using.