1. Preheat oven to 400 degrees. Line a muffin pan with 9 paper liners or spray with cooking spray. Set aside.
2. In a medium bowl, whisk together flour, salt, and baking powder.
3. In a small bowl, add the sugar and lime zest. Rub sugar and zest together until fragrant. Add sugar and zest to the flour mixture. Whisk ingredients together.
4. In a glass measuring cup or small bowl, mix canola oil, egg, buttermilk, lime juice, and vanilla extract together.
5. Pour the wet ingredients over the flour mixture. Slowly stir together, the batter will be thick. Don't over mix. Gently fold in the blackberries.
6. Fill 9 muffin cups with the batter. Sprinkle each muffin with turbinado sugar.
7. Bake muffins for 17-20 minutes, or until muffins are golden brown and a toothpick comes out clean. Let muffins cool on a cooking rack.
*Note-you can use frozen berries, but try to use fresh blackberries. They make these muffins extra special. This recipe only makes 9 muffins, feel free to double it.