1. Preheat oven to 400°. Trim beet stems to 1 inch; gently wash beets. Wrap individually in aluminum foil, and place on a jelly-roll pan.
2. Bake at 400° for 1 hour or until tender. Transfer to a wire rack, and let cool, wrapped in foil, 30 minutes.
3. Meanwhile, decrease oven temperature to 350°. Bake pecans in a single layer in a jelly-roll pan 5 to 7 minutes or until lightly toasted and fragrant. Cool completely on wire rack (about 15 minutes).
4. Whisk together vinegar and next 5 ingredients in a small bowl. Add oil in a slow, steady stream, whisking constantly until smooth.
5. Peel beets, and remove stem ends. Cut beets into 1/2-inch wedges; gently toss with 1/3 cup vinegar mixture.
6. Arrange greens on a serving platter. Top with beet mixture, Gorgonzola cheese, and pecans; serve with remaining vinaigrette.