In a large mixing bowl, beat the softened butter, granulated sugar, and brown sugar until light and fluffy.

Add the egg and vanilla extract, mixing until smooth and well combined.

In a separate bowl, whisk together the all-purpose flour, baking soda, salt, and cinnamon (if using).

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Avoid overmixing.

Gently fold the blueberries into the dough. If using, add the white chocolate chips for extra sweetness.

Cover the dough and refrigerate for at least 30 minutes to prevent spreading while baking.

Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

Using a tablespoon or cookie scoop, drop dough balls onto the baking sheet, spacing them 2 inches apart.

Bake for 10–12 minutes, or until the edges turn golden. The centers may look slightly underbaked but will set as they cool.

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