Melt butter in a large Dutch oven; add lamb, 1/2 teaspoon salt, pepper, garlic salt, and savory. Sauté over medium heat until lamb is browned.
Add flour; blend until smooth. Add tomatoes and potatoes. Cover; simmer 20 minutes over low heat. Add water; cover and cook 20 minutes. Add remaining salt; stir well. Serve over toast points.