1To prepare the vinaigrette, combine blueberries, shallot, vinegar, sugar, and salt in blender or food processor and process until blended. Add olive oil gradually and process until smooth.
2To prepare the salad, trim tough stems from spinach. Place one radicchio leaf on each of 8 plates. Top with 1 cup of spinach and sprinkling of blueberries, pecans and feta cheese. Drizzle with vinaigrette.