Line a medium pot with a thin layer of water. Over hight heat, saute onions and garlic until water has absorbed, about 3 minutes. Add remaining ingredients and bring to a boil. Continue to cook about 15 minutes, or until lentils are fully cooked (they have expanded and are orange). Add salt to taste. Transfer 1/2 of soup to blender and puree or use an immersion blender and puree until smooth. Return to pot and mix with remaining soup. Turn off heat, cover and let rest 5-10 minutes, allowing flavors to merge before serving.