Clean and prep your vegetables.
Add avocado oil to 6-quart (or larger) dutch oven and heat over medium-high heat.
Use paper towel to pat the short ribs dry and then season all sides with kosher salt.
Once the pan and oil is hot, sear the short ribs on all sides.Note: I like to sear the short ribs for the deep rich flavor, however if short on time, you can skip this step and add them in with the vegetables and broth. Once browned, transfer the short ribs to a clean plate and drain and discard majority of the oil in the pot, leaving only a little behind.
To the pan, add the carrots, onion and leeks with a pinch of kosher salt. Stir and cook 2 minutes, scraping any browned bits off the bottom of the pot.
Add in the turnips and mushrooms. Pour in the beef stock, add the barley and stir.Add the browned short ribs back in, cover the pot and heat over medium-low for 3 hours, stirring occasionally. Once time is up, use tongs to remove the short rib bones. Chop the meat (discarding any tough or fatty pieces) and add the beef back into the soup along with the peas. Stir and heat through - should only take a minute.
Season with kosher salt and freshly ground black pepper to your preference.