In a large skillet, heat the vegetable oil over medium-high heat. Add the beef cubes and brown them on all sides, about 5-7 minutes. Remove the beef and set aside.

In the same skillet, add the sliced onion and cook until softened, about 5 minutes. Add the minced garlic and cook for an additional minute.

Sprinkle the flour over the onions and garlic, stirring to combine. Cook for 1-2 minutes to eliminate the raw flour taste.

Gradually pour in the dark beer, scraping up any browned bits from the bottom of the skillet.

Return the beef to the skillet and add the beef broth, thyme, rosemary, bay leaf, brown sugar, apple cider vinegar, salt, and pepper. Stir to combine.

Transfer the mixture to a slow cooker and cook on low for 7-8 hours or on high for 4-5 hours, until the beef is tender.

Before serving, remove the bay leaf and adjust seasoning if necessary. Garnish with fresh parsley.