Melt your butter or margarine, if using, in a medium size pot. Then add the shallots, garlic, and sliced mushrooms and sprinkle with salt and pepper. Sauté until reduced, approx 6-8 minutes.
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 35-40 minutes, stirring occasionally.
Once cooked, add a little more salt and pepper, to taste, and serve garnished with fresh parsley, 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 6-8 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 desired and serve garnished with fresh parsley.
If you're avoiding oil, sauté in water or broth instead.Once the broth is added, cook your soup with the pot's lid on, but slightly askew. This will ensure your broth doesn't evaporate too much while the barley is cooking.