Patriotic 4th of July Cupcakes

Preheat oven to 350°F (177°C). Prepare a muffin tin with liners or lightly grease each cavity with cooking spray.
In a stand mixer, ½ cup unsalted butter and 1 cup sugar together. Add 1 large egg, ¼ cup sour cream, and 1 ½ teaspoon vanilla extract.
In a separate medium bowl, whisk together dry ingredients (1 ⅔ cup all-purpose flour, ¼ teaspoon baking soda, ½ teaspoon baking powder, ½ teaspoon salt).
Alternate between adding dry ingredients to wet ingredients in stand mixer and whisking in ¾ cup milk slowly. Whisk until batter is just smooth, but do not over mix.
In a small bowl, toss 1 tablespoon flour with ⅓ cup blueberries and ⅓ cup raspberries. Use a spoon to scoop out fruit into the mixing bowl, leaving the remaining flour in bowl. Gently fold fruit into the batter.
Pour batter into the lined muffin tin, filling cupcake liners about halfway full. Bake for 18-20 minutes until cupcake centers bounce back to the touch. Allow cupcakes to cool on baking rack.

Meanwhile, make the buttercream icing. Using a hand mixer, whip softened 1 cup unsalted butter in a medium size mixing bowl.
Add in 1 cups powdered sugar and continue beating mixture.
Add remaining 2 cups powdered sugar, one cup at a time.
Add in 1 teaspoon vanilla, 1 teaspoon salt and 2 tablespoons heavy cream. Beat until consistently mixed.
Ice cupcakes once cooled completely. Use a piping bag and tip or spatula to ice cupcakes. Top each one with a few ½ cup fresh blueberries and ½ cup fresh raspberries.
Store in refrigerator for up to one week.