Pat beef stew meat dry, season with salt and pepper, dust with flour. In a large Dutch oven, heat oil and sear beef for about 5 minutes per side. Remove and set aside.

In the same pot, sauté diced onion for about 5 minutes. Add minced garlic and cook for an additional minute. Stir in tomato paste and cook for 2 minutes.

Pour in Irish ale, scraping up browned bits with a wooden spoon. Return beef, add broth, Worcestershire sauce, thyme, bay leaves, carrots, parsnips, and optional potatoes. Stir and bring to a simmer.

Cover pot, reduce heat to low, and simmer gently for 2 to 2½ hours, stirring occasionally, until beef is tender and shreds easily.

Meanwhile, boil peeled potatoes and garlic until tender (15-18 minutes). Drain, mash with butter, milk, and optional sour cream until creamy.

To serve, ladle stew over garlic mashed potatoes, garnish with parsley and cracked pepper. Enjoy warm.