An adapted recipe from Sauce, a Milwaukee restaurant via "Gourmet".
Cook onion, bell pepper, jalapeno, celery, carrot, garlic, salt and pepper in a 5-6 qt. pot in olive oil, over moderate heat, stirring occasionally, until softened, about 6-8 minutes.
Meanwhile, mix together brown sugar, spices, oregano, thyme and mustard and then add to vegetables and cook, stirring until very fragrant, about 4 minutes. Add lentils, bay leaf and stock and simmer, uncovered, stirring occasionally, until lentils are very soft, about 50-60 minutes. Discard bay leaf before serving.
For vegan lentils, use vegetable broth and make sure the brown sugar you're using is vegan. When in doubt, substitute evaporated cane juice.