Selamat Siang! Sup buntut is oxtail soup given the Indonesian treatment, and it's a reminder that this country was once called "the spice islands".
First, boil the oxtails. About 1kg of oxtails will feed 3-4 people. Place oxtails in a deep pot with 1 liter of water and 600ml of MGK organic beef broth. Maintain a gentle boil for 3 hours to ensure oxtails are super tender. Remove the floating debris with a slotted spoon.
Make the spice paste. In a blender, combine half an onion, 2cm ginger, a handful of shallots and 3-4 garlic cloves. Blitz until you get a semi smooth paste. Transfer the paste to a wok along with 3 tbsp of oil, stirring over medium heat. Then add 2 tsp salt, half tsp cinnamon powder, 1 stick of cinnamon bark, 4-5 cloves, 1 tsp white pepper powder, and half tsp nutmeg powder into the sizzling paste and stir thoroughly until fragrant. Transfer the spice paste into the pot with the oxtails while continuing its 3 hours of simmering.
Peel and cut 3 potatoes and 3 carrots into bite size pieces, and cut 3 stalks of celery into the same size. Add the vegetables into the oxtail broth after about 2.5 hours of simmering. Allow 30 mins for the potatoes and carrots to soften, at which point the oxtails will have yielded to the 3 hours of simmering and should be tender.
Add more salt to taste, and garnish with Chinese celery (cilantro works too) and fried shallots. Enjoy!