if using, blanch the tripe to clean any residual chlorine from the bleaching process. Place the tripe in a large pot and cover with water and a couple teaspoons of salt. Boil for about 10 minutes, strain and rinse well under cold water.
Cut the tripe into strips about 1 inch wide by 2-3 inches long and set aside.
Prep the vegetables - cut the eggplant into bite size pieces, the green beans into about 2 inch pieces, and the baby bok choy in half or quarters depending on size.
If using oxtails sear them in a pot on all sides and set aside.
Sauté the onions on vegetable oil for 2-3 minutes to soften slightly.
Add the garlic and sauté until fragrant.
If using stew meat or other cuts of beef add them now and cook to get some color. if using oxtails add them back in to the pot with the onion and garlic.
Once the beef is browned add in the stock and bring that to a boil. Reduce it to a simmer and cook covered for 1.5-2 hours (3 if using oxtails) until the beef is tender.
Add in the anatto water, peanut butter, and crushed peanuts stirring to melt the peanut butter into the sauce. Taste and add salt and pepper if needed.
Once that is well combined add the eggplant and cook for 5-7 minutes stirring occasionally.
Next add the green beans and allow them to cook for 3-5 minutes.
Turn off the heat and add the bok choy on top. Cover with the lid and allow it to steam for about 5 minutes to wilt the leaves. The green beans and centers of the bok choy should still have a little crisp.
Serve with shrimp paste and steamed rice on the side.