1 lb butter (4 sticks or 2 cups) at room temperature
5 cups icing sugar (confectioners' or powdered)
1 teaspoons pure vanilla extract
1/4 cup whipping (35% fat) cream
1/4 cup whole milk
1 teaspoon dried culinary lavender
A few drops of lavender food colour (or equal parts blue and red)
Add 1 teaspoon of dried culinary lavender to 1/4 cup whole milk, cover, and refrigerate overnight (or at least several hours). Strain into clean bowl.
In a bowl of stand mixer fitted with paddle attachment, combine the icing sugar and butter and beat on low speed for about 1 minute. Add vanilla and beat on low until well combined. Add whipping cream, lavender milk, and food colouring (if using), and beat on med-high speed for another 3 minutes, until light and fluffy. Best used right away.