Cut a piece of parchment paper to fit the bottom of your slow cooker. place parchment paper in bottom of slow cooker and then spray parchment paper and sides of slow cooker with nonstick cooking spray.
Pour 1 cup of batter in bottom of slow cooker. sprinkle the blueberries on top of the batter.
Top with remaining 1/2 cup of batter.
Cover and cook on high for 1 hour (or until toothpick inserted in center comes out clean).
Loosen edges of the pancake with a butter knife and turn slow cooker over to let pancake fall out onto a plate.
Whisk lemon juice milk and powdered sugar together in a small bowl and drizzle over the top of the pancake.