Place a large heavy pot over medium heat and add the bacon. Fry for about 5 minutes until crisp and remove to a paper towel and reserve. Add the beef to the hot bacon fat and brown it evenly on all sides, turning with tongs; season generously with salt and pepper. While the beef is searing, sprinkle the flour evenly in the pot and continue to stir to dissolve any clumps. Add a little oil if necessary to keep the meat from sticking to the bottom of the pot.
Toss in the onions, garlic, roasted peppers, paprika, and caraway; cook and stir for 2 minutes until fragrant. Stir in the vinegar, tomatoes, and broth. Bring to a boil, then lower to a simmer and cook for 1 hour, covered, stirring occasionally.
Add the potatoes. Crumble the reserved bacon into the stew and continue to simmer for 30 minutes, partially covered, until the potatoes are tender. Season with salt and pepper. Remove from heat and stir the sour cream into the goulash just before serving. Garnish with the chopped parsley.