A rich and tomato sauce with vegetables makes for an easy weeknight meal. The bucatini stands up nicely to the hearty sauce.
Add the butter and one tablespoon of butter to a Dutch oven over medium-high heat. Add the mushrooms and saute for 3-5 minutes, until nicely browned. Remove the mushrooms from the pot and set aside.
Add the remaining olive oil to the pan along with the diced onion and bell pepper. Saute the vegetables until the onions are translucent, about 2-3 minutes. Then add the meatloaf, salt, and pepper and saute until the meat is browned, breaking it up as you go.
Now add the mushrooms back to the pot along with the marinara sauce, crushed red pepper, bay leaf, and red wine vinegar. Bring to a boil; then reduce to a simmer. Allow to simmer for at least 30 minutes and up to an hour.
While the sauce simmers, cook the bucatini according to the package directions. Make sure to salt your pasta water!
Add the pasta to the meat sauce, stirring to combine. Top with freshly grated parmigiano-reggiano and serve!