Heat the oil in a large Dutch oven or black iron pot over medium heat, add the kielbasa and saute for 8 to 10 minutes, until browned. Remove the kielbasa to a bowl, and set aside. Add the ham to the same pot and cook 8 to 10 minutes, until lightly browned. Remove to the bowl with the kielbasa, and set aside. Add the butter, onion, celery and peppers to the same pot and saute for 8 to 10 minutes, until the onion is translucent. Add the tomato, garlic, jalapeno or cayenne, oregano, thyme, and tomato paste and cook until all the vegetables and herbs are blended well. Add the stock and bring to a rolling boil. Stir in the rice, and add the sausage, ham, bay leaves, salt, pepper and hot sauce. Return to a boil, reduce the heat to low and simmer, covered, for 20 minutes. Add 1/4 cup of the scallions, 1/4 cup of the parsley, the lemon juice and the shrimp, and stir well. Cover the pot, remove it from the heat and allow the jambalaya steam, for 15 minutes, before serving.

Garnish with the remaining 1/4 cup scallions and 1/2 cup parsley, and a dash of hot sauce, if desired.