Cook Brussels sprouts and 1 tablespoon salt in boiling water 6 minutes or until almost tender. Drain and plunge into ice water; drain well.
Cook pancetta in a large skillet over medium-low heat until crisp, stirring occasionally. Remove pancetta from pan, reserving drippings.
Cut Brussels sprouts in half lengthwise; place on a baking sheet. Add reserved drippings, 1/4 teaspoon salt, and pepper; toss to coat. Bake at 450° for 15 minutes or until browned, stirring after 10 minutes. Combine Brussels sprouts, pancetta, and vinegar in a large bowl; toss well.