Make croutons: melt butter with olive oil in heavy large skillet over medium heat. Add bread cubes and stir gently until golden brown. Drain on paper towels and set side.
Melt 1 T. butter in heavy Dutch oven over mediium heat. Add ham and cook 5 minutes, stirring occasionally. Add 6 cups stock, lentils, chili, and savory. Cover and bring to boil. Reduce heat and simmer until lentils are tender but firm to bire, stirring occasionall, about 30 minutes.
Heat oil in heavy large skillet over medium heat. Add onions, carrots and bell pepper. Stir until vegetables begin to soften, about 5 minutes. Add garlic and cook 2 minutes. Stir mixture into soup. Add enough stock to cover.
Wipe out skillet. Add 3 T. butter and melt over medium-low heat. Add flour and stir until light, about 6 minutes. Whisk in 2 cups stock. Bring to boil, whisking constantly. Add to soup. Stir in the tomato puree and 3 T. vinegar. Bring to boil. Reduce heat, cover and simmer 30 minutes, stirring occasionally. Thin soup to desired consistency with stock. Season with remaining 1 T. vinegar, salt and generous amount of pepper. Discard chili. Garnish soup with Sauteed Croutons and serve.