Place blueberries and lemon juice and zest in a small saucepan over medium heat. Stirring occasionally, let the blueberry mixture cook until the blueberries are softened and a syrup has formed, about 12-15 minutes. Remove from heat and let sit until cool.

Once the blueberry mixture has cooled, add to a mixer fitted with the whisk attachment. Add the butter to the mixer, and whisk on high until the blueberry mixture is well combined with the butter.

Add the powdered sugar, vanilla extract, and salt to the mixer, and whisk on low until the powdered sugar is well incorporated. Scrape down the bowl, and then turn the mixer on high, whisking until the mixture is light and fluffy, about 10 minutes. Switch the whisk to the paddle attachment, and whip on high for an additional 5 minutes.