Start by thawing the frozen blueberries and pre-heating the oven to 350 degrees F. Place the frozen blueberries in a sealable bag, and place that bag in some hot water until thawed. Line a 9 by 9 baking dish with parchment paper and spay with cooking spray.
Using a hand held mixer, cream the 8 tbsp of butter and 3/4 cup granulated sugar until smooth. Add the 1 tsp vanilla extract and 2 eggs, and continue to mix until well combined, about 20 seconds. Pour in the thawed blueberries and mix.
Add the flour, 1 tsp baking soda and 1/2 tsp of salt to the blueberry mixture and mix on medium speed until fully combined. Fold in the chocolate chips.
Press a little over half of the blue cookie batter into the parchment lined baking pan, reserving the other half.
Now make the cream cheese mixture. Using the cleaned hand held mixer, combine the softened cream cheese, 1/4 cup sugar, 1 egg and 1/2 tsp vanilla extract until fully mixed. Pour this mixture over the top of the pressed cookie in the pan, and spread evenly over the top.
Now place the rest of the cookie mixture on top of the cream cheese layer. You have the option to make a design, or just place bits of the cookie mixture wherever you like.
Bake at 350 degrees for 35-40 minutes. NOTE that the cheesecake will still be slightly 'jiggly', but that the cookie part should be fully cooked through.
Allow to rest at room temperature for at least 20 minutes before transfering to the counter and cutting into squares! Enjoy!