Cook 1/3 cup of blueberries in a small saucepan over medium heat for about 5 minutes, mash lightly, then add lemon juice and sugar to taste. Stir until thickened and cool completely.

In a stand mixer, combine 1 cup of softened unsalted butter and 2 tablespoons of whole milk. Beat on low for 1 minute, then increase to medium-high and beat for 5 minutes until fluffy.

Gently add in 2 tablespoons of maple syrup, a pinch of kosher salt, cooled blueberry sauce, and seeds from half a vanilla bean. Mix on low until incorporated.

Scoop the blueberry butter into an airtight container or decorative dish. Serve at room temperature or refrigerate for up to a week.