Season the beef cubes with salt and black pepper, then toss with the all-purpose flour until coated. Brown in batches in the butter or oil over medium-high heat until deeply browned, about 6-8 minutes total per batch, and transfer to a plate as the beef gives off a clear, roasted color.

Cook the sliced onions in the same Dutch oven over medium heat for 8-10 minutes until golden, scraping up any browned bits. Add the minced garlic, tomato paste, sweet paprika, and caraway seeds and cook for 1 minute until fragrant.

Pour in the German dark beer and scrape the pot thoroughly to dissolve the browned fond. Stir in the beef broth, Dijon mustard, red wine vinegar, and bay leaves, then return the beef to the pot and bring to a gentle simmer.

Cover and simmer on low until the beef is tender, about 1 1/2 hours, keeping bubbles steady but not rolling. Check occasionally for a gentle simmer and add a splash of broth only if the pot looks dry.

Add the cubed potatoes and sliced thick carrots, then cover and simmer 45-60 minutes until tender when pierced with a fork. Watch for the vegetables to soften while the sauce thickens and clings to the meat.

Remove the bay leaves, then top the stew with chopped fresh parsley. Let it sit 5 minutes off the heat so the flavors settle, and serve hot.