In a large pot over medium heat, heat 2 tablespoons oil or bacon fat. Add ham and cook until beginning to brown, 8 to 10 minutes. Use a slotted spoon to transfer ham to a bowl. Raise heat to medium-high and add remaining 2 tablespoons oil or fat to the pan. Add onion, celery, jalapeño peppers, bell pepper, bay leaf, 1 teaspoon salt and the black pepper; cook until lightly browned, 8 to 10 minutes, stirring frequently. (Add a little water, if necessary, to prevent burning on the bottom of the pot.) Stir in garlic and cook another 2 minutes. Add stock, beans, collard greens, reserved ham and remaining 1 teaspoon salt. Bring to a boil, then reduce heat, party cover, and simmer for 30 minutes, stirring occasionally. Add parsley, vinegar and more salt to taste. Serve topped with hot sauce and sour cream if you like.