Salt and pepper your beef shanks, and set aside. Heat a dutch oven on med-low heat, and add the bacon. Gently sauté the bacon on med-low heat until most of the fat has been rendered out. Remove the bacon with a slotted spoon.
Raise the heat to med-high heat, and brown the shanks on both sides, about four minutes per side. Set the shanks aside.
Reduce the stove heat to medium, and preheat your oven to 325 degrees. Add the chopped onion and diced carrot to the remaining bacon grease, and sauté until aromatic, about three minutes. Add the tomato paste and garlic, and sauté for another two minutes. Return the beef and bacon to the dutch oven, then pour in the 1/2 bottle of red wine, spices, and enough beef broth to mostly cover the beef shanks. Bring to a simmer.
Cover and place in the oven for two and a half hours. When there’s an hour left, add the two coarsely chopped carrots to the dutch oven.
Once you add the carrots, it’s time to get the rest of the dish prepped. To get the pearl onions ready, drop them into some boiling water for about five minutes, then fish them out and put them in a bowl of ice water. Once they’ve cooled, you should be able to cut each end of them off and slide them out of their outer layer easily. Set them aside.
Quarter your mushrooms and set them aside. Also, peel your potatoes (cut them in half if they’re pretty big) and add them to a pot of cold water. Bring to a boil and gently simmer until fork tender, about 10 minutes. Drain and rinse with cold water.
Melt the butter in a pan on medium heat, then add the potatoes, mushrooms, and onions. Sauté for about eight minutes, until the mushrooms start to soften and look a little wet. Remove from the heat and set aside.
After the beef is ready (easily pierced with a fork), remove the beef and carrots with some tongs and set aside. Pour the remaining sauce into a fat separator lined with a cheese cloth. Take whatever is left in the cheesecloth (your soggy looking bacon, carrots, and onions) and blend it into a paste.
Pour the leftover wine/broth sauce (minus the fat) back into the dutch oven, and bring to a simmer on medium heat. Add the paste you just made as well, and continue to simmer for a few minutes as it reduces.
Meanwhile, cut your beef into large chunks, arrange your plates, and pour the sauce on top. That’s it!