A delicious, seriously delicious soup recipe. Taken from Jan/Feb 2013 Cooks Illustrated. The zest and chives really lighten up the flavor. Also, let the soup stand, it tastes amazing after several minutes of resting!
Adjust oven rack to middle and heat oven to 375 F.
Grind shitake mushrooms in spice grinder until finely ground (~ 3 tbsp).
Bring 4 1/2 cups of water, thyme, bay leaf, garlic glove, 3/4 tsp salt, and baking soda to a boil in medium saucepan over high heat. Add rice and bring to a boil. Cover saucepan, transfer to oven and bake until tender (45-50 minutes at altitude). Strain rice through fine-mesh strainer, collect rice broth for cooking liquid (3 cups). Remove the thyme, bay leaf and garlic.
Melt butter in Dutch oven over high heat. Add creminis, onion, minced garlic, tomato paste, 3/4 tsp salt, 1 tsp pepper. Cook, stirring occasionally until vegetables are brown and dark fond develops on bottom of pot, 15 minutes. Add sherry, scraping up any browned bits and cook until reduced and pot is almost dry (~ 2 minutes). Add ground shitakes, reserved rice cooking liquid, broth and soy sauce and bring to boil. Reduce heat to low and simmer, covered, until the onion and mushrooms are tender.
Whisk cornstarch and remaining 1/4 cup water in a small bowl. Stir the slurry into soup, retun to simmer and cook until thickened (~ 2min). Remove pot from heat and stir in cooked rice, cream, chives and lemon zest. Cover and let stand 20 minutes.