Gather ingredients and preheat oven to 350℉. Prepare 2 large cookie sheets with parchment.
Combine room temperature butter, brown sugar, and granulated sugar in a large mixing bowl and mix until creamy and well-combined.
In a separate bowl, combine flour, salt, and baking powder. Whisk until combined.
Beat together the large egg, cinnamon, and vanilla extract. Add it to the creamed butter and sugar. Mix with a hand mixer until combined.
Little by little, add some of the dry flour mixture to the wet mixture until a sticky dough forms and all of the flour mixture has been used up.
Gently fold in the frozen blueberries and white chocolate chips.
Using a cookie scoop (I use a 1.25 oz. cookie scoop), portion out cookies on the lined baking sheets, leaving 2 inches of space between cookies.
Baking in the middle rack of 350℉ oven for 15-20 minutes, or until the cookies have spread out and have just a touch of golden color around the edges. (In my oven, they took 15 minutes. In the Budget Bytes oven, they took 20 minutes!) I like my cookies a little chewy, so I pull them right when I start to see them looking a little golden on the tops or edges.
Transfer to a cooling rack and let cool 10-15 minutes before you enjoy!
*The cinnamon didn’t make it into my ingredient photo, but it’s a must! It really makes the flavor of the blueberries shine, so don’t forget it.**Make sure your blueberries (even if you’re using fresh) are fully frozen when you add them to the dough! If they are soft, they will squish as you fold them in and the dough will become too wet. I like to use the big bags of Wyman’s wild blueberries for these cookies because the berries are a bit smaller and easier to handle, but any variety of blueberry will do. I can find these berries at both my local Kroger and Walmart with ease.For the best results, follow the mixing steps in order. Cream the butter and sugars together first, then add the egg, cinnamon, and vanilla. Only then should the remaining dry ingredients be added. This creates the best blueberry cookies with a soft, chewy middle and lightly crisp edges!Add a few extra white chocolate chips on top: To achieve showstopping, beautiful cookies, press a couple of extra white chocolate chips into the top of each ball just before baking!Make the dough fresh: I don’t recommend refrigerating the mixed dough once the blueberries are folded in, because the berries can thaw and release juice.