Preheat oven to 350 degrees. Spray an 8x8-inch baking dish with cooking spray.
Toss the berries with the Swerve Granulated and spread evenly into the bottom of the prepared baking dish. Cut the cream cheese into small pieces and scatter evenly over the top of the berries.
Combine the cake mix, eggs, oil, water, and vanilla in a mixing bowl and whisk until smooth. Pour over the top of the berries and cream cheese evenly. Bake for 50-60 minutes or until golden brown. Let cool 10 minutes before dusting with Swerve Confectioners and serve.