Preheat your oven to 375°F and line two baking sheets with parchment paper. In a medium bowl, whisk together flour, baking soda, and salt until well combined.

In a large mixing bowl, cream the softened butter and sugar together for 2-3 minutes until the mixture becomes light and fluffy. Beat in the egg and vanilla extract until smooth and well combined.

Alternate adding the flour mixture and sour cream to your creamed butter, beginning and ending with flour. Mix just until combined – don't overmix.

Toss your blueberries with one tablespoon of flour in a small bowl. Gently fold the flour-coated berries into your dough using a wooden spoon or rubber spatula.

Using a cookie scoop or spoon, drop rounded tablespoons of dough onto your prepared baking sheets, spacing them about 2 inches apart. Bake for 12-14 minutes until the edges are set and lightly golden – the centers should still look slightly soft and pale.

Let the cookies rest on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.