Place the stock in a sauce pot and warm it over medium heat then reduce to simmer.
Heat the extra-virgin olive oil and the butter in a large, deep skillet over medium to medium-high heat. Add the pancetta to brown slightly. Next add the garlic and spaghetti and toast the noodles lightly, 3 to 4 minutes. Add onions and carrots, bay leaf and thyme, and season with salt and pepper. Soften veggies a bit, 5 minutes. Add wine and allow it to be completely absorbed. Add beans then add a few ladles of stock and stir the pasta. Keep adding stock a few ladles at a time allowing liquids to be mostly absorbed before adding more, as if you were preparing a risotto. When liquids are absorbed and spaghetti is cooked to al dente, 12-15 minutes, stir in cheese. Adjust salt and pepper. Turn off heat and stir another minute. Remove the bay leaf and thyme stems. Serve in shallow bowls and garnish with lots of parsley.