Remove rind from the slab of salt pork. Slice the salt pork into 1/4-inch slices and then into 1/4-inch batons.
Place into a small saucepan of boiling water and reduce heat.
Simmer for 10 minutes and then drain; dry well with paper towels.
Set aside; both the rind and the batons will be used.
Preheat the oven to 450°F (225°C).
Heat 1 tablespoon olive oil in a Dutch oven over medium heat.
Sauté the batons of salt pork for 2 to 3 minutes until lightly browned.
Remove the salt pork from the pan with a slotted spoon and put on a plate; set aside.
Raise the heat under the Dutch oven to medium high and add your dried beef cubes to the oil, a few at a time, as not to crowd them. There must be space between them otherwise they won't brown properly.
Brown the cubes on all sides, then remove the and add them to the plate with the salt pork. Repeat the browning until all the beef is used.
Next, sauté the carrot and sliced onion until brown using the same fat.
Pour off any excess fat.
** Note: in Mastering the Art of French Cooking, Julia actually never says what to do with the sautéed carrot and onion. Once they are sautéed, they are never mentioned again! Some references say remove them, while others just keep them as part of the stew. In this version, I removed them but have kept them at other times. I actually watched her French Chef episode on this - I believe it was the very first episode of the series - and she didn't have the salt pork, carrot, onion or any flour. Go figure...
Return the beef and salt pork to the Dutch oven and season with the salt and pepper.
Then sprinkle with the flour and toss to coat.
Place the Dutch oven in the preheated oven for 4 minutes, remove and toss the beef, then bake for an additional 4 minutes. This process toasts the flour.
Reduce oven heat to 325°F (170°C).
Add the wine and 2 cups beef stock to the meat, so that the meat is barely covered. If necessary, add more stock to cover the beef.
Add the tomato paste, herbs and reserved bacon rind.
Bring it to a simmer on top of the stove, then cover it and place it in the oven.
Check after 15 minutes to make sure the stew is at a simmer. If it is more than a simmer, reduce heat. Conversely, if it isn't simmering, raise heat 5°.
The meat should be done in about 3 hours - and will be very tender when pierced with a fork. Some cuts of meat (bottom round, for example) might take longer - up to 4 hours.
While the beef is in the oven, prepare the onions and mushrooms.