Place the short ribs, onion, ginger, chicken broth, water and soy sauce in a multicooker/pressure cooker (such as the Instant Pot). Cover with the valve set to "pressure" and cook on High pressure for 30 minutes.
Depressurize the pressure cooker; if you have time, allow the pressure cooker to sit and depressurize on its own, this will allow the short ribs even more time to tenderize.
As the broth cooks, heat the olive oil in a large saute pan. Add the mushrooms and soy sauce, and cook for about 5 minutes, or until wilted. Set aside.
Bring a large pot of water to a boil. Drop in the noodles and cook for two minutes. Drain the noodles and divide into four large bowls.
When the pressure cooker is done, open the pressure cooker and let it sit on the simmer function for a few minutes, or until any oil rises to the surface. Use a large spoon to skim the excess fat from the broth. If you have time, the broth can be done the day before or earlier in the day; cool and refrigerate the broth and it will be easier to separate the fat from the broth.
Drop in the baby bok choy and tofu (if using) and let that simmer for about 4 minutes.
To serve, spoon the broth over the noodles, placing some short rib, Shiitake mushrooms, bok choy, and tofu in each bowl. Garnish with a soft boiled egg, if using. Serve immediately.
Short Rib Ramen Tips
Don’t have a pressure cooker (Instant Pot)? No problem, you can make the broth in a regular large pot; it will just take longer to cook. Simply place the broth ingredients in a large pot, and bring to a boil over high heat. Cover and lower heat to a simmer, and cook until the short ribs are tender; this may take anywhere from 1-3 hours, depending on the size of your short ribs.
What kind of short ribs do I use? This recipe uses English style short ribs, where the ribs are cut parallel to the bone, with one large piece of meat attached to the bone. This makes for a very meaty presentation and a delicious broth!
Make ahead: The broth can be made a day in advance, and reheated when ready to serve. The advantage to this is it makes it easier to separate the fat from the broth by chilling the broth and skimming fat before reheating — the short ribs will definitely release a lot of fat, and while that’s amazing for flavor, removing some fat is a good idea!