Step 1: Prepare the Steak
Pat the steak cubes thoroughly dry with paper towels. This is the single most important step for achieving a proper sear. Season liberally on all sides with kosher salt, black pepper, and the optional smoked paprika. Let them sit at room temperature for 15-20 minutes to take the chill off.

Step 2: Sear to Perfection
Heat a large cast-iron skillet or heavy-bottomed stainless steel pan over medium-high heat until it is very hot, almost smoking. Add the high-smoke-point oil and swirl to coat. Working in batches to avoid overcrowding (which steams the meat), add the steak cubes in a single layer. Do not move them for 2-3 minutes, allowing a deep, brown crust to form.

Step 3: Develop the Crust
After 2-3 minutes, use tongs to flip each cube to sear another side. Continue cooking and turning for a total of 4-6 minutes for medium-rare, or until the cubes are browned on most sides and reach your desired internal temperature (125°F for rare, 135°F for medium-rare). Transfer the seared bites to a plate. The pan will have glorious browned bits (fond) stuck to the bottom—this is flavor gold.

Step 4: Create the Sauce (The Magic Moment)
Reduce the heat to medium-low. Immediately pour the wine, broth, or bourbon into the hot, empty skillet. Use a wooden spoon to scrape up all the browned fond from the bottom of the pan (deglazing). Let the liquid reduce by half, about 1 minute.

Step 5: The Garlic Butter Baste
Add the cold butter to the reduced liquid. As it melts, add the minced garlic and whole rosemary sprigs. Swirl the pan constantly, letting the garlic become fragrant but not burn (about 1 minute). The mixture will foam and become creamy. Stir in the Worcestershire sauce and lemon juice.

Step 6: The Grand Finale
Return all the seared steak bites and any accumulated juices back to the skillet. Toss and roll them in the bubbling garlic butter sauce for 1-2 minutes, spooning the sauce over them continuously. This allows the meat to finish cooking gently and absorb the incredible flavor.

Step 7: Garnish and Serve
Remove from heat. Discard the rosemary sprigs. Stir in half of the fresh parsley. Transfer the steak bites and every drop of sauce to a serving platter. Sprinkle with the remaining parsley and a pinch of flaky sea salt. Serve immediately with toothpicks and plenty of crusty bread for the sauce.