Step 1

Sprinkle beef all over with salt and pepper. Heat 1 tablespoon oil in a large heavy pot over medium-high heat. Add half of the beef; cook, turning to brown on 2 or 3 sides, about 3 minutes per side. Transfer the browned beef to a bowl; repeat the process with the remaining beef and 1 tablespoon oil.

Step 2

Add onion, carrots and celery to the drippings in the pot; cook, stirring often, until the vegetables begin to soften, about 4 minutes. Add tomato paste; cook, stirring constantly, for 1 minute. Add beer and thyme; cook, scraping the bottom of the pot to release any browned bits, until the liquid is slightly reduced, about 2 minutes. Add broth and the beef (with any accumulated juices in bowl); bring the mixture to a boil over medium-high heat. Reduce heat to medium-low; cover and cook until the beef is mostly tender, about 1 hour, 10 minutes. Stir in potatoes; cover and cook until the beef and potatoes are tender, 15 to 20 minutes.

Step 3

Whisk cornstarch and cold water in a small bowl. Increase heat to high; add the cornstarch mixture and cook, stirring constantly, until thickened, about 2 minutes. Remove from heat; stir in parsley. If desired, garnish with additional parsley.