This not-too-sweet gluten free blueberry hazelnut coffee cake is an ode to Portland, Oregon, where hazelnuts, blueberries and weekend brunches reign supreme. With this cake, you can celebrate and savor all three, anytime, anywhere.   Blueberry Hazelnut Coffee Cake   Author: Camilla V Saulsbury Ingredients Filling 2⁄3 cup chopped toasted hazelnuts 1⁄4 cup packed dark