In a large bowl or pot add the beans and cover with water by 2 inches.
Soak for 8 hours or overnight. Drain and set aside.
In a large pot over medium-high heat melt the bacon grease . Add the tasso or ham and cook, stirring, for 1 minute.
Add the onions, celery and bell peppers to the grease in the pot. Season with the salt, pepper, and cayenne, and cook, stirring, until the vegetables are soft, about 4 minutes.
Add the bay leaves, parsley, thyme, sausage, and ham hocks, and cook, stirring, to brown the sausage and ham hocks, about 4 minutes.
Add the garlic and cook for 1 minute. Add the beans and stock or water, stir well, and bring to a boil. Reduce the heat to medium-low and simmer, uncovered, stirring occasionally, until the beans are tender and starting to thicken, about 2 hours. (Should the beans become too thick and dry, add more water, about 1/4 cup at a time.).
Remove from the heat and with the back of a heavy spoon, mash about 1/4 of the beans against the side of the pot. Continue to cook until the beans are tender and creamy, 15 to 20 minutes.