In a medium saucepan over medium heat, combine fresh blueberries and granulated sugar. Mash the berries with a potato masher, cooking for about 8-10 minutes until the mixture thickens to a jam-like consistency. Allow it to cool to room temperature; refrigerating speeds up this process.
In a large mixing bowl, beat together the softened cream cheese and salted butter until the mixture becomes light and fluffy. This should take about 2-3 minutes for the best texture. Next, add the vanilla extract and mix until fully combined. Gradually add the powdered sugar, beating until thick and fluffy.
Slowly incorporate the cooled blueberry reduction into your frosting, mixing until you achieve an even, vibrant color and delightful taste.
Transfer the frosting into a piping bag and get creative! Use it to decorate cupcakes, layer cakes, or even a bundt cake, showcasing its beautiful hue.