Woodsy porcini hold their own in this satisfying and fiber-filled white bean stew. Enriched by tomatoes, an excellent source of lycopene, and infused with garlic and rosemary, each bowl offers a flavorful way to eat well.
Bring stock and 1/2 cup water to a boil in a small pan. Add porcini. Let stand until soft, about 20 minutes. Remove porcini with a slotted spoon; coarsely chop. Set aside. Strain soaking liquid through cheesecloth; set aside.
Heat oil in a medium pan over medium-high heat. Add onion, garlic, salt, and pepper. Cook, stirring occasionally, until onion is translucent, about 3 minutes. Add white mushrooms; cook, stirring occasionally, until tender, about 5 minutes. Stir in porcini, tomatoes, rosemary, soaking liquid, and beans. Bring to a boil. Reduce heat to medium; simmer until cooked through, about 15 minutes. Remove cooked rosemary; discard. Garnish with fresh rosemary sprigs.