1. Use fresh or frozen blueberries 2. if using frozen do not thaw 3. toss berries in flour to reduce sinking and bleeding 4. do not overmix to avoid a tough loaf 5. tent loosely with foil if top browns before center is done 6. swap buttermilk with 0.75 cup milk mixed with 1 tbsp lemon juice and rested 5 minutes 7. store airtight at room temperature 3 days or freeze sliced up to 2 months