Cook the bacon in a stockpot over medium heat until crisp. Using a slotted spoon, remove the bacon to a paper towel-lined plate. Keep the bacon drippings in the pot for the next step.

Stir together the flour, salt and pepper in a shallow dish. Add the beef to the mixture, and toss to coat. Brown the beef in the reserved bacon drippings. Remove and set aside. Editor's Tip: To avoid overcrowding the pot with beef, brown the meat in batches as needed. Transfer the browned beef to a plate, and continue browning the rest of the pieces in batches.

Add to the same pot the mushrooms, leeks, carrots, celery and oil. Cook over medium heat until the veggies become tender. Add in the minced garlic, and cook for one minute more.

Stir in the tomato paste, then add the broth, beer and dried herbs. Add the browned beef and cooked bacon. Bring to a boil. Reduce to a simmer, then cover and cook until the beef is tender, about two hours.

Add the cubed potatoes to the stew, and return the mixture to a boil. Reduce the heat to low, cover the pot, and cook for about one hour, until the potatoes are fork-tender.

Whisk together the cornstarch and cold water in a small dish, then stir the mixture into the stew. Bring the stew back to a boil; cook and stir everything for two minutes, until the stew is thickened. Finally, stir in the frozen peas. Once the peas are heated through, remove and discard the bay leaves. Serve.