01 - In a shallow dish, whisk together the all-purpose flour, kosher salt, black pepper, and smoked paprika until evenly combined.
02 - Pat the cube steaks dry with paper towels. Dredge each steak through the seasoned flour mixture, coating both sides thoroughly, then shake off any excess.
03 - Heat the vegetable oil and 1 tablespoon of butter in a large skillet over medium-high heat. Once the fat is shimmering, add the coated steaks and sear for 2 to 3 minutes per side until a golden-brown crust forms. Work in batches to avoid crowding the pan. Transfer the seared steaks to a plate and set aside.
04 - Reduce the heat to medium and add the remaining tablespoon of butter to the same skillet. Add the sliced onions and sauté for about 5 minutes until softened and translucent. Stir in the sliced mushrooms and continue cooking for 3 additional minutes until lightly caramelized.
05 - Pour the beef broth and Worcestershire sauce into the skillet, using a wooden spoon to scrape up any browned bits from the bottom of the pan. Bring the liquid to a gentle simmer.
06 - Return the seared cube steaks to the skillet, nestling them down into the onion and mushroom mixture. Reduce the heat to low, cover with a lid, and let simmer for 30 to 35 minutes until the beef is fork-tender and the gravy has thickened.
07 - If using, stir in the heavy cream during the final 5 minutes of cooking for a richer, creamier gravy. Taste and adjust the seasoning with salt and pepper as needed. Serve hot, spooning generous amounts of gravy over each steak.