Preheat oven to 325 degrees. In a medium bowl, whisk together the beef broth, flour, and tomato paste. Set aside. Make an herb bouquet with parsley, rosemary, thyme, and bay leaves by placing it in a large square of cheesecloth and tying it with kitchen twine, or by simply tying the herbs together – cheesecloth will prevent any pieces from coming off into the sauce, but it’s not completely necessary if you don’t have it.
In a large, heavy French or Dutch oven with a snug fitting lid, cook the bacon or pancetta over medium heat until cripsy and all fat has been rendered. Remove the bacon/pancetta to clean bowl and set aside. Add enough ghee to equal roughly 1/4 cup of fat.
Season beef with salt & pepper. Add half of the beef to the pot and brown on all sides, remove to the bowl with the bacon, and repeat with the remaining beef, removing it the same bowl when browned.
Add the sherry wine followed by the shallots and cook for 5 minutes, stirring occasionally. Give the beef broth mixture a good whisk or two, and pour into the pot. Increase heat to medium-high and bring to a rapid boil. Stir in the red wine. Return the beef to the pot, and nestle the herb bouquet in the center.Cover and braise in the preheated oven for 2.5 hours.
Melt the butter in a large skillet and saute the mushrooms. Remove the herb bouquet from the pot and discard. Stir the mushrooms into the sauce and serve over mashed potatoes with a sprinkle of parsley for garnish (if using) and side of cooked carrots and buttered bread.