Step 1

Preheat your oven to 350°F (175°C).

Step 2

Line baking sheets with parchment paper to prevent sticking.

Step 3

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

Step 4

Add the mashed bananas, egg, and vanilla extract. Mix until the batter is smooth and well combined.

Step 5

In a separate bowl, whisk together the flour, baking soda, salt, and ground cinnamon.

Step 6

Gradually add the dry ingredients to the wet ingredients. Mix gently to avoid overworking the dough.

Step 7

Carefully fold in the fresh blueberries, chopped walnuts, and rolled oats. Be gentle to keep the blueberries intact.

Step 8

Scoop tablespoon-sized portions of dough onto the prepared baking sheets, spacing them about 2 inches apart.

Step 9

Bake for 12-15 minutes, or until the edges are golden brown.

Step 10

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