- Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper. 
- In a large bowl, combine the rolled oats, whole wheat flour, brown sugar, baking soda, and salt. Mix well. 
- In another bowl, cream together the softened butter, egg, and vanilla extract until smooth. 
- Gradually add the dry ingredients to the wet ingredients, mixing until just combined. 
- Gently fold in the chopped strawberries and walnuts, if using. 
- Drop spoonfuls of the cookie dough onto the prepared baking sheet, spacing them about 2 inches apart. 
- Bake for 12-15 minutes or until the edges are lightly golden. 
- Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.