Step 1In a large heavy saucepan heated over medium-high heat, add the butter and olive oil and saute onion until tender, 3 to 5 minutes, stirring occasionally. Add celery and cook until softened, 5 minutes longer.
Step 2Add the tomatoes, water, lentils, barley, one-half teaspoon salt, one-fourth teaspoon pepper and the rosemary. Bring to a boil, cover and simmer over low heat 25 minutes, stirring occasionally, until the barley and lentils are almost tender.
Step 3Add carrots and cook 5 minutes longer, or until the barley and lentils are tender.