For the stovetop

1. Toss cubed beef in a large bowl with 2 tablespoons all-purpose flour, 1/2 teaspoon kosher salt, and 1/4 teaspoon pepper.
2. To a large Dutch oven set over medium-high heat, add 2 tablespoons olive oil. Working in two batches, add the beef when the oil is hot and shimmering. Cook, stirring occasionally until all sides are deeply browned, about 8 minutes. Using a slotted spoon, transfer beef to a mixing bowl and set aside.
3. Turn the heat down to medium and add the remaining 2 tablespoons olive oil. Then, add the diced onion, diced carrots, and diced celery and cook, stirring occasionally, until the vegetables are golden brown, about 7 to 10 minutes. Add minced garlic, 2 tablespoons fresh minced rosemary, 1 teaspoon dried thyme, potatoes, and 3 tablespoons of tomato paste and cook, stirring often, for 1 to 3 minutes until fragrant. Add 1 cup of red wine, a little bit at a time, to deglaze the pan, and use a wooden spoon to stir up all the brown bits on the bottom. Add the 12 ounces of stout beer and bring to a simmer. Simmer for 5 minutes while scraping browned bits from the bottom of the Dutch oven, then add 2 cups of beef broth, 1 tablespoon of Worcestershire sauce, 1 (28-ounce can of diced Italian plum tomatoes, 2 bay leaves, and return the browned beef to the pot, and stir to combine.
4. Reduce heat to medium-low, cover Dutch oven and simmer until meat is tender, about 1 to 1/2 hours, adding 1/4 cup of additional beef broth if the stew becomes dry. If you want your stew thicker, add the cornstarch slurry at the end of the simmering time. To serve, remove bay leaves and divide stew between 8 shallow serving bowls. Top with chopped parsley. Serve immediately.

For the slow cooker

1. Toss cubed beef in a large bowl with 2 tablespoons all-purpose flour, 1/2 teaspoon kosher salt, and 1/4 teaspoon pepper.
2. In a large Dutch oven or skillet over medium-high heat, add 2 tablespoons of olive oil. Brown the meat in batches until golden brown.
3. Using a slotted spoon, transfer beef to the slow cooker. Add the remaining 2 tablespoons of olive oil, diced onion, diced carrots, and diced celery and cook, stirring occasionally, until the vegetables are golden brown, about 7 to 10 minutes.
4. Transfer everything to the slow cooker and add minced garlic, 2 tablespoons fresh minced rosemary, 1 teaspoon dried thyme, potatoes, 3 tablespoons of tomato paste, 1 cup of red wine, 12 ounces of stout beer, 2 cups of beef broth, 1 tablespoon of Worcestershire sauce, 1 (28-ounce can) of diced Italian plum tomatoes, 2 bay leaves, and stir to combine.
5. Cook on low for 8 hours or high for 4-6 hours.
6. Add cornstarch slurry in the final hour, if desired. 
7. To serve, remove bay leaves and divide stew between 8 shallow serving bowls. Top with chopped parsley. Serve immediately.

For the Instant Pot

1. Toss cubed beef in a large bowl with 2 tablespoons all-purpose flour, 1/2 teaspoon kosher salt, and 1/4 teaspoon pepper.
2. Turn on the sauté function and add 2 tablespoons of olive oil. Brown the meat in batches until golden brown.
3. Using a slotted spoon, transfer beef to a mixing bowl and set aside. Add the remaining 2 tablespoons of olive oil, diced onion, diced carrots, and diced celery and cook, stirring occasionally, until the vegetables are golden brown, about 7 to 10 minutes. Add minced garlic, 2 tablespoons fresh minced rosemary, 1 teaspoon dried thyme, potatoes, 3 tablespoons of tomato paste, 1 cup of red wine, 12 ounces of stout beer, 2 cups of beef broth, 1 tablespoon of Worcestershire sauce, 1 (28-ounce can) of diced Italian plum tomatoes, 2 bay leaves, and return the browned beef to the pot, and stir to combine.
4. Pressure cook on high for 35 minutes.
5. Natural pressure release for 10 minutes, then quick release.
6. Using sauté mode, add the cornstarch slurry, if desired. To serve, remove bay leaves and divide stew between 8 shallow serving bowls. Top with chopped parsley. Serve immediately.