01 - In a shallow dish, whisk together the flour, salt, black pepper, and paprika until evenly combined. Reserve 2 tablespoons of the seasoned flour mixture and set aside for thickening the gravy later.
02 - Pat the cube steaks dry with paper towels. Dredge each steak through the seasoned flour, pressing gently to coat both sides thoroughly. Shake off any excess flour and transfer to a clean surface.
03 - Heat the vegetable oil and 1 tablespoon of butter in a large skillet over medium-high heat until the butter foams and subsides. Working in batches if necessary, sear the dredged cube steaks for 2 to 3 minutes per side until a deep golden crust forms. Transfer the browned steaks to a plate and tent loosely with foil.
04 - Reduce the heat to medium. Add the remaining tablespoon of butter to the skillet along with the sliced onions and mushrooms. Cook, stirring occasionally, for 6 to 8 minutes until the onions are softened and the mushrooms are deeply caramelized.
05 - Add the minced garlic and the reserved 2 tablespoons of seasoned flour to the skillet. Stir continuously for 1 minute to cook out the raw flour taste and bloom the garlic.
06 - Slowly pour in the beef broth and Worcestershire sauce, stirring constantly while scraping up all the browned bits from the bottom of the skillet. Pour in the milk and stir to combine. Bring the liquid to a gentle simmer.
07 - Nestle the seared cube steaks back into the skillet, spooning some of the gravy over the top. Cover with a tight-fitting lid, reduce the heat to low, and simmer for 20 minutes until the steaks are fork-tender and the gravy has thickened to a rich, coating consistency.
08 - Taste the gravy and adjust the seasoning with additional salt and pepper as needed. Transfer the steaks to serving plates, ladle the onion-mushroom gravy generously over each portion, and garnish with freshly chopped parsley. Serve immediately alongside mashed potatoes, steamed rice, or buttered egg noodles.