Preheat oven to 250 degrees F.
Heat the olive oil in a large Dutch oven. Add the bacon and cook over medium heat for 8 to 10 minutes, stirring occasionally, until the bacon is lightly browned. Remove the bacon with a slotted spoon to a plate.
Dry the beef cubes with paper towels and then sprinkle them with salt and pepper. In batches, in single layers, sear the beef in the hot oil for 3 to 5 minutes, turning to brown on all sides. Remove the seared cubes to the plate with the bacon and continue searing until all the beef is browned. Set aside.
Toss the carrots, onions, 1 T of the salt and 2 t of the pepper into the fat in the pot and cook over medium heat for 10 to 12 minutes, stirring occasionally, until the onions are lightly browned. Add the garlic and cook for 1 more minute. Add the Cognac (stand back and ignite with a match to burn off the alcohol). Put the meat and the bacon back into the pot with any juices that have accumulated on the plate. Add the wine plus enough beef broth to almost cover the meat. Add the tomato paste and thyme. Bring to a boil, cover the pot with a tight-fitting lid and put it in the oven for about 1 1/4 hours, or until the meat and veggies are very tender when pierced with a fork. Remove from the oven and put on top of the stove.
Combine 2 T of the butter and all of the flour with a fork and stir into the stew. Add the frozen onions. In a medium pan, saute the mushrooms in the remaining 2 T of butter over medium heat for 10 minutes, or until lightly browned, and then add to the stew. Bring the stew to a boil, then lower the heat and simmer uncovered for 15 mintues. Season to taste.
Rub each slice of bread on one side with the garlic. For each serving, spoon the stew over a slice of bread and sprinkle with parsley.
Note: if the sauce is too thin, you can add more of the butter and flour mixture.