Heat the olive oil in a large Dutch oven over medium-high heat. Add the lamb pieces and brown them on all sides, about 6 to 8 minutes. Remove the lamb to a plate and set aside.
Lower the heat to medium. Add the onion, garlic, and carrots to the pot. Cook for 5 minutes until the onion softens.
Return the lamb to the pot. Stir in the diced tomatoes, broth, rosemary sprigs, oregano, salt, and pepper. Bring the mixture to a boil.
Reduce the heat to low, cover the pot, and simmer for 1 hour until the lamb is tender.
Add the white beans and continue simmering uncovered for 15 minutes to let the flavors blend and the stew thicken slightly.
Remove the rosemary sprigs. Ladle the stew into bowls and finish each serving with a squeeze of lemon juice.