Step 1

Adjust oven rack to lower-middle position and heat oven to 325 degrees. Season beef with salt and pepper. Heat oil in Dutch oven over medium-high heat until shimmering. Add onions and ¼ teaspoon salt and cook, stirring occasionally, until well browned, 8 to 10 minutes.

Step 2

Add tomato paste and garlic and cook until rust-colored and fragrant, about 2 minutes. Stir in flour and cook for 1 minute. Whisk in broth, ¾ cup Guinness, sugar, and thyme, scraping up any browned bits. Bring to simmer and cook until slightly thickened, about 3 minutes. Stir in beef and return to simmer. Transfer to oven and cook, uncovered, for 90 minutes, stirring halfway through cooking.

Step 3

Stir in potatoes and carrots and continue cooking until beef and vegetables are tender, about 1 hour, stirring halfway through cooking. Stir in remaining ½ cup Guinness and parsley. Season with salt and pepper to taste, and serve.