To cook lentils: Place in a saucepan, cover with at least 1 inch of water, bring to a simmer and cook until just tender, 15 to 30 minutes, depending on the type of lentil. Drain and rinse with cold water. 1 cup dry lentils = about 2 1/2 cups cooked. Or use canned lentils: 15-ounce can = 1 1/2 cups. Rinse canned lentils before cooking with them to reduce the sodium by 35%.