In the meantime, heat the oil in a medium sauté pan over medium-high heat, and sauté carrot, onion, celery, green pepper and garlic for 5-8 minutes, until deep golden brown but not mushy. Stir into lentils with vinegar, honey, salt and black pepper, and up to a quarter cup of juice from any meat or poultry being served with the lentils (like duck). Cook over medium heat for 3-5 minutes to marry the flavors.