In a large bowl, combine 2 cups flour, 1/4 cup sugar, baking powder and cinnamon. Then add the eggs, milk and oil and stir until moistened (batter will be very thick). Coat the slow cooker with cooking spray then spread the batter evenly into slow cooker (I used a 6 quart).
In a separate large bowl, combine the salt, remaining flour and sugar. Add the berries in the bowl and toss to coat. Pour on top of the batter in the slow cooker.
Place the lid on the slow cooker and cook on high for 2 hours (or until a toothpick inserted into cobbler comes out clean). Serve immediately with French vanilla ice cream if desired.