Melt the butter, if using, in a medium pot. Then add the shallots, garlic, and sliced mushrooms. Sauté until reduced, approx. 5-6 minutes, and then sprinkle with salt and pepper.
Add the broth and barley, and bring to a boil with the lid on your pot, but slightly askew. Cook over medium/high heat until the barley is tender, approx. 40-45 minutes, stirring occasionally.
Once cooked, add a little more salt and pepper, if needed, and serve garnished with fresh parsley or red pepper flakes, if desired.
Instant Pot Instructions
Set your Instant Pot to the sauté function and add the butter to melt, if using. Add the shallots, garlic and sliced mushrooms and sprinkle them with salt and pepper. Sauté until reduced, approx. 5-6 minutes.
Add the broth and the barley and close the lid. Make sure you set the valve to the sealing position and set to high pressure for 22 minutes. It will take about 10-15 minutes to build pressure and begin counting down.
Once the timer is complete, quick release the steam valve and open the lid once safe to do so. Season with more salt and pepper, if needed and serve garnished with fresh parsley or red pepper flakes.
Notes
Cook your soup with the lid on but slightly askew. Cooking without the lid will cause too much of the broth to evaporate. Barley has a long cook time, so it will appear like a lot of liquid at first, but the barley will absorb more and more as it cooks.For no oil, use water or broth to sauté the veggies.If time permits, you may add more veggies to the sauté step. Chopped carrots and celery would make great additions. Or add some baby spinach to the very end of cooking, if desired.Leftovers keep refrigerated for 3-4 days, or you may freeze in a freezer-safe, airtight container for up to 3 months.