1. Heat oven to 375 degree F. Place blueberries in a 9-1/2-inch pie dish or a 9-inch square baking pan and stir in 3 tablespoons flour and granulated sugar. In a medium bowl, combine the oats, remaining flour, brown sugar, and cinnamon. Cut in the butter until the mixture resembles coarse crumbs. Stir in the nuts. Sprinkle topping evenly over the blueberries and bake 40 to 45 minutes, covering top with foil halfway through. Serve warm with creme fraiche or whipped cream, if desired. Makes 8 servings.