<ol><li>In a large bowl, mix romaine lettuce, endive and radicchio. Set aside.</li><li>To make dressing, preheat a 2-qt. sauté pan or 10-in. omelette pan over medium-high heat until rim of pan is hot to the touch.</li><li>Add bacon and cook, stirring often, until crisp, about 3 - 5 minutes.</li><li>Stir in onion, pepper, celery seeds, rosemary, thyme and mustard. Cook, stirring often, until onion is gold around edges, about 2 - 3 minutes.</li><li>Add cider vinegar, balsamic vinegar and sugar. Bring to a boil; remove from heat and stir in oil. Season to taste with salt.</li><li>Peel and core pears; cut into thin wedges. Mix pears into greens, then transfer salad to a rimmed platter or large salad bowl.</li><li>Pour warm dressing over salad and mix. Garnish with pecan halves, if desired. Serve at once.</li></ol>