A juicy, seared steak is a sure route to maximal flavor with minimal effort. But when chefs want to really raise the steaks, they add a not-so-secret ingredient: butter. It not only delivers rich flavor, but also helps the meat achieve a beautiful, brown crust. To that end, you’ll be basting sirloin in butter, garlic, and herbs in this recipe. The sides are no slouch, either: parsnip wedges roasted until they’re sweet, plus tender spinach decked out with sour cream.