Cook bacon over medium low heat until golden brown and crisp, but not hard. Do not overcook. Remove bacon with a slotted spoon and set aside. Remove half of the bacon drippings and set aside.

Combine flour, salt and pepper in a large bowl and stir to combine. Add beef and toss with your hands to coat.

In a large Dutch oven or heavy duty pot, heat bacon fat over medium high heat until hot, but not smoking. Add ½ of the beef and spread out to cover the bottom of the pan. Cook, undisturbed until the beef is golden brown on the underside, about 5-7 minutes. With a large metal spatula, flip beef to uncooked side and cook until second side is golden brown. Remove with a slotted spoon to a clean plate. Add the rest of the bacon fat to pot. Heat until hot, add remaining beef and repeat cooking process as directed above.

Once second batch of beef is browned, return first half of beef to pan. Add onion and garlic and cook for 2-3 minutes. Add tomato paste and 1 of cup wine. Bring to a boil then lower heat to maintain a low simmer. Continue cooking, stirring occasionally to loosen brown bits from bottom of pan. (I like to use a thin bladed metal spatula for this.) Simmer until most of the wine is absorbed, about 20 minutes then add the remainder of the wine and simmer until almost completely absorbed .

Add the beef stock, thyme, bay leaf, pesto and brown sugar and return to a boil. Reduce to a low constant simmer, cover and cook for 1 hour or until beef is tender. Remove bay leaf and thyme sprigs.

Add celery, carrots and potatoes, cover loosely and cook till tender, about 20-25 more minutes.

While vegetables are cooking, melt butter in a sauté pan over medium-high heat. When butter is bubbly, add mushrooms and salt. Cook, stirring occasionally until mushrooms are golden brown, about 10-15 minutes. Add mushrooms and bacon to soup and stir. If soup is too thick add a bit more stock or water. Taste and add salt and freshly ground black pepper, if needed.Serve in bowls with warm crusty bread on the side.