Whisk together the melted butter and sugars until combined. Add the egg and vanilla, and mix until combined.
Add the dry ingredients, and mix until just combined. Gently fold in the blueberries.
Cookies stay fresh, kept in an airtight container, at room temperature for up to 1 week.
Cookie dough balls can be kept in the fridge for up to 5 days, or frozen for up to 3 months. Bake from frozen.
The calories are an estimate only.