Set your oven to 350°F and place paper liners in a 12-cup pan to simplify cleanup later.

Using a fork, softly press ⅓ cup of blueberries in a small bowl to release a bit of juice, don’t mash them.

Add the buttermilk and vanilla, then set the mixture aside to let the flavors meld.

Beat the butter, oil, granulated sugar, and brown sugar in a large bowl until smooth, pale, and airy.

Scrape the bowl's edges with a spatula, then mix for another 1 to 2 minutes until fully combined.

Beat in the egg until well blended, followed by the egg white, mixing until the batter turns silky and smooth.

Slowly pour the blueberry-buttermilk mixture into the batter while mixing on low speed. Continue mixing until the batter is smooth.

Mix the cake flour, baking powder, and salt in another bowl, whisking until evenly incorporated.

Add this to the wet ingredients and mix on low or gently fold it in by hand until just combined.

Gently mix the remaining ⅓ cup of blueberries with a bit of flour, then fold them into the batter with care. This simple step prevents the berries from dropping to the base during baking.

Fill each cupcake liner with batter, aiming to fill them around three-quarters full. 

Bake for 20 to 22 minutes, or until the tops are golden and a toothpick inserted in the center comes out clean and dry. 

Cool the cupcakes in the pan for 10 minutes before transferring them to a wire rack to cool entirely.

For the frosting, turn freeze-dried blueberries into a fine powder with a food processor.

In a mixing bowl, combine the softened butter and cream cheese by beating them until smooth and evenly incorporated. 

Stir in the powdered sugar, vanilla, and a pinch of salt, then mix on low until everything is combined. 

Turn up the speed and continue mixing for 2 to 3 minutes, until the mixture is airy and light.

Add the blueberry powder to the frosting and beat for another 2 minutes until it’s well combined and fluffy, turning a beautiful purple color.

Once the cupcakes are completely cool, spread the frosting on top, either with a butter knife or piping bag, and enjoy!