In a large bowl, combine the flour, 3/4 cup sugar, baking powder, salt, cinnamon and nutmeg. Combine the eggs, milk and oil; stir into dry ingredients just until moistened. Spread the batter evenly onto the bottom of a greased 5-qt. slow cooker. , In a large saucepan, combine the berries, water, orange zest and remaining sugar; bring to a boil. Remove from the heat; immediately pour over batter. Cover and cook on high for 2 to 2-1/2 hours or until a toothpick inserted into the batter comes out clean., Turn cooker off. Uncover and let stand for 30 minutes before serving. Serve with whipped cream or ice cream if desired.