Adjust oven rack to the lower-middle position and preheat to 325°F. Sprinkle beef with 1 teaspoon salt. Process red peppers, paprika, tomato paste, and 2 teaspoons vinegar in a food processor until smooth (1-2 minutes), scraping down the sides as needed.

In a Dutch oven, combine onions, oil, and remaining 1 teaspoon salt. Cover and cook over medium heat, stirring occasionally, until onions soften but have not browned (8-10 minutes). If browning begins, reduce heat and stir in 1 tablespoon water.

Stir in the pepper mixture and cook uncovered until onions start to stick to the bottom of the pot (2 minutes). Stir in beef, carrots, and bay leaf, scraping down the pot's sides. Cover and transfer to the oven.

Bake until beef is almost tender and liquid is reduced to 1/2 inch below the top of the meat, stirring every 30 minutes (2 to 2 1/2 hours). Add broth as needed to maintain liquid levels.

Stir in additional broth until the liquid measures 1/2 inch below the meat's surface. Cover and cook until beef is tender (about 30 minutes). Remove pot from oven and discard the bay leaf. Skim excess fat from the surface, adjust consistency with broth, and stir in remaining vinegar. Season with salt and pepper to taste.

Serve hot with sour cream and buttered egg noodles for an authentic touch.