• Preheat oven to 325 F.

Set a large Dutch oven over medium-high heat and add the oil. Once it starts shimmering, add the onions and 1/4 teaspoon salt. Cook for 8-10 minutes, stirring occasionally, until the onions have browned. Stir in the tomato paste and garlic and cook for about 2 minutes, or until fragrant and rust-colored. Add the flour and cook, stirring constantly, for 1 minute (just to get rid of the raw taste). Mix in the chicken broth, 3/4 cup of the Guinness, the brown sugar, and the thyme leaves. Scrape the bottom of the pot to pick up any browned bits.

Bring the mixture to a simmer and cook for a few minutes until it has thickened slightly. Season the beef generously with salt and pepper, and add to the pot. Return the mixture to a simmer, then transfer the pot to the oven (uncovered).

Cook for 90 minutes, stirring once halfway through the cooking time. Remove the pot from the oven and add the potatoes and carrots, stirring to distribute. Return the pot to the oven and cook for another 60-90 minutes, stirring at 30-minute intervals. The stew is ready when the veggies and beef are fork-tender. Remove the pot from the oven and stir in the remaining 1/2 cup of Guinness and the parsley. Season to taste with salt and pepper and serve.