In a food processor or blender, puree carrots, onions, celery and garlic.
In a large pot, heat oil over medium heat. Add pureed vegetables and season generously with salt. Bring the pan to a medium-high heat and cook, stirring occasionally until all water has evaporated and veggies become nice and brown, about 15-20 minutes.
Add the ground beef and season again generously with salt. Cook another 15-20 minutes--don't rush this step.
Add the tomato paste and cook about 4-5 minutes. Add the red wine and cook until wine has reduced by half, about 4-5 minutes. Add water to pan just until the meat is covered. Toss in bay leaves and thyme bundle. Stir.
Bring sauce to a boil and then reduce heat to a simmer, stirring occasionally (about every 20 minutes). As the water evaporates , you will gradually need to add more, a half cup at a time.
Taste and season as needed. Simmer for 3 1/2 to 4 hours.
During the last 30 minutes of cooking, bring a large pot of water to boil and cook spaghetti one minute less than the package calls for. Reserve 1/2 cup of the pasta water.
While pasta is boiling, stir in cream and remove bay leaves and thyme.
Remove half of the sauce from the pot and reserve. Drain pasta and add to the pot with the remaining sauce and the reserved pasta water as needed. Toss to coat adding some of the reserved sauce if needed. Cook the pasta and sauce over medium heat until water is reduced.
Turn off the heat and sprinkle generously with parmigiana. Toss vigorously and serve.
Freeze any leftover sauce for another time