Heat a deep pot over medium high heat and add oil and pancetta. Brown the pancetta bits lightly, and add herb stems, bay leaf, chopped vegetables, and garlic. Season vegetables with salt and pepper. Add beans, tomato sauce, water, and stock to pot and raise heat to high. Bring soup to a rapid boil and add pasta. Reduce heat to medium and cook soup, stirring occasionally, 6 to 8 minutes or until pasta is cooked al dente. Rosemary and thyme leaves will separate from stems as soup cooks. Remove herb stems and bay leaf from soup and place pot on table on a trivet. Let soup rest and begin to cool for a few minutes. Ladle soup into bowls and top with lots of grated cheese. Pass crusty bread for bowl mopping.