Prepare all your vegetables.
Prepare the oxtail by washing them under a tap to remove any small pieces of bone. Dry the oxtail with a paper towel and trim off as much excess fat as you want. (Note 1)
In a fry pan, add 1 tbsp of oil and saute all the vegetables for 10 minutes on medium high.
After 10 minutes, add the sauteed vegetables to the pressure cooker and the rest of the meat sauce ingredients except the oxtails. Stir with a wooden spoon until completely combined. Then add the oxtails and cover them in the sauce,
Cook on high pressure (I use the meat / stew setting) for 50 mins to 1 hour. (Note 2)
Carefully depressurize the cooker and remove the lid as instructed in your pressure cooker manual.
Using a spoon, remove the desired amount of fat suspended on top of the sauce. (Try to leave some fat since it adds great flavour and richness to the sauce)
Remove the oxtails from the pot and let them cool. Once they can be handled, pull the meat off into chunks and add them back to the sauce. Or skip this step and serve the oxtails whole.
Boil plenty of water with a good pinch of salt and cook the pasta as directed on the packaging. Strain your pasta once it's done.
Check the seasoning of your sauce and adjust according to your taste. Also, check the thickness of your sauce. Allow the sauce to reduce further if you like it richer and thicker by using the saute function on your pressure cooker.