Place all ingredients for dressing in a bullet blender. Seal the blender and puree for 15-30 seconds or until the blackberries are broken down. Taste the dressing, add more vinegar if it is too sweet for you tastes. Set dressing aside.
If you don't have a bullet blender you can smash the thawed frozen blackberries with a fork in a bowl and whisk all the ingredients together.
For raw pine nuts: Heat a small frying pan over low heat, add pine nuts and toast for several minutes until they brown slightly and become fragrant. Sprinkle with a bit of salt and set aside.
Peel and thinly slice the shallot. Halve the avocado, remove the pit and peel and then thinly slice it.
In a large bowl, add spinach and top with the shallot, avocado, pine nuts, washed blacker berries and basil. Dress salad last with as much dressing as you would like. Serve immediately and save any extra dressing in an airtight container.
** Fresh blackberries can be used in the dressing, but frozen blackberries will breakdown easier and puree smoother.