Season the steak with ½ teaspoon salt and ¼ teaspoon black pepper.
Heat the olive oil in a large Dutch oven over medium-high heat.
Add half the steak in a single layer and sear for 2 minutes per side, until browned.
Transfer the browned steak to a plate.
Repeat with the remaining steak, then reduce the heat to medium.
Add the onion, carrots, and celery. Cook for 5 minutes, stirring occasionally, until they begin to soften.
Add the garlic and cook for 30 seconds.
Stir in the tomato paste, thyme, rosemary, and smoked paprika. Cook for 1 minute, stirring constantly.
Pour in the beef broth and chicken broth.
Scrape the bottom of the Dutch oven with a wooden spoon to loosen the browned bits.
Add the potatoes, Worcestershire sauce, bay leaf, remaining ½ teaspoon salt, and remaining ¼ teaspoon black pepper.
Return the steak and any juices from the plate to the Dutch oven.
Bring the soup to a gentle boil over medium-high heat.
Reduce the heat to medium-low, cover, and simmer for 20 to 25 minutes, until the potatoes are fork-tender and the steak is cooked through.
While the soup simmers, blend the cottage cheese and milk until completely smooth.
Remove the bay leaf from the soup and reduce the heat to low.
Ladle ½ cup of hot soup broth into the cottage cheese mixture and stir until combined.
Slowly pour the cottage cheese mixture into the soup, stirring constantly.
Heat gently for 3 to 5 minutes, without boiling, until the soup is hot and slightly creamy.
Stir in the chopped parsley.
Notes
Tips and Tricks
Choose Lean Steak – Sirloin works great because it cooks relatively quickly and stays tender when you avoid overcooking it. Trim any large pieces of fat before cutting.Keep the Potato Pieces Even – Similar-sized cubes cook at the same rate, so you won't end up with some potatoes falling apart while others are still firm.Blend Until Smooth – Take a little extra time blending the cottage cheese. A smooth mixture gives the broth a creamier texture without noticeable curds.Avoid Boiling After Adding Dairy – High heat can cause the cottage cheese mixture to separate. Gentle heat helps keep the broth creamy.Adjust the Thickness – The potatoes may absorb some broth as the soup sits. Add a little extra low-sodium broth if you prefer a thinner soup.
Storing and Reheating
Refrigerating – Allow the soup to cool slightly, then transfer it to airtight containers. Refrigerate within 2 hours and store for up to 3 to 4 days.Freezing – Freezing is possible, but the potatoes can become grainy and the dairy-based broth may separate after thawing. For the best texture, enjoy this soup fresh or refrigerated.Reheating on the Stovetop – Heat leftovers in a saucepan over medium-low heat, stirring occasionally, until they reach 165°F. Avoid a rapid boil to help prevent the creamy broth from separating.Reheating in the Microwave – Place a serving in a microwave-safe bowl, cover loosely, and heat in short intervals, stirring between each one, until the soup reaches 165°F.