Cut the bacon into ½” x 2” strips and sauté in olive oil in a cast-iron skillet over medium heat. When lightly browned, set the bacon aside while leaving the grease in the skillet. Raise the temperature until almost smoking and lightly brown the beef in small batches and set aside with the bacon.
Partially cook the onions until soft and translucent with just a touch of singing around the edges. Set them aside in a small bowl to be used later.
Partially cook the mushrooms in the same skillet using the bacon grease and drippings from the meat until they've just started to reduce and have soaked up the remaining bacon grease. Then, set them aside to be used later
Preheat the oven to 375°F. Return the beef and bacon to the cast-iron skillet and toss with the salt, pepper, and flour. Cover and place in the oven to cook all the way through, tossing once in the middle. (about 8 min total)
Create a herb bouquet by crushing the various herbs by hand and wrapping them in cheese cloth. Tie off the bundle with some string to close, and be sure to leave plenty of extra string.
In a large soup pot, combine the meat with the red wine, tomato paste, herbs, herb bouquet, and enough beef stock to just cover the meat. Bring to a simmer on the stovetop and cook until the meat is soft and crumbling, stirring occasionally. (3-4 hours)
With about 30 min remaining on the previous step, add butter and olive oil to the cast-iron skillet. Once the butter foams, add the reserved onions and sautée over medium heat until the onions are evenly browned, taking care not to break their skins. Add the beef stock, salt, and black pepper. Simmer until the onions are tender and the liquid has evaporated. Set the onions aside.
Clean the skillet and heat another portion of butter and olive oil over high heat. Once the butter foams, add the mushrooms. Sautée until soft and translucent. Set the mushrooms aside.
Once the meat is finished cooking, discard the herb bouquet, and strain the meat while retaining the liquid. Place the meat in a large serving dish, and add first the mushrooms and then the onions on top. Cover, and set aside in the oven (turned off) to keep warm.
Reduce the retained liquids in a large saucepan over high heat. Skim the fat from the top as it rises. Continue to simmer until the sauce has the consistency of heavy cream. When finished, gently add the sauce to the serving dish. (about 20 min)