Use the saute setting to saute 2 finely chopped onions until they've become translucent, then add 2 T of sambal ulek or 2 finely chopped chilipeppers and stir for 5-6 minutes.
Add the 2 stems lemongrass smashed and tied into a knot, 4 makrut lime leaves, 2 Indonesian bay leaves, 4 cm of galengal, 2 cm of turmeric.
Add the 500 gr of beef cut into rough chunks and stir so the meat is coated in the spice mix. Add 1 1/2 T of brown sugar, stir and add 1/2 c water to deglaze the pan. Turn off saute mode.
Add 1 T of fish sauce and marrowbone (if using), cover and set to seal. Cook on high pressure for 35 minutes.
Allow for natural release for 10 minutes (i.e. don't manually release the pressure until after 10 minutes have passed).
Remove the lemongrass, lime and bay leaves, galengal and turmeric (you don't have to but this just makes stirring a little easier and the flavors have already developed during the pressure cooking process).
Add 200 ml of coconut milk. Set to saute and stir gently until the liquid has cooked down fully and has started to release it's oil. This can take up to between 30 mins and 1 hour. Stir gently to avoid the meat breaking apart too much. If you notice the meat is so tender it breaks up too much, take out the meat and reduce down the liquids as far as you can instead, before adding the meat back in.