Say goodbye to same-old steak dinners—and hello to this decadent dish, designed for family-style dining (or for all the leftover-lovers out there). This recipe puts a seasonal spin on au gratin, the French technique of baking veggies—usually potatoes—with a cheesy sauce and crunchy breadcrumbs. Here Swiss chard and butternut squash are mixed with nutty Gruyère and baked to gooey perfection, then served with juicy seared steak and a decadent red wine pan sauce. Prepare to see steak dinners with new eyes (and a grumbling stomach).
Cutting meat against the grain ensures tenderness. Find the direction of the grain (muscle fibers) and slice across it, rather than parallel.
“Deglazing” is a technique in which adding liquid to the pan after cooking protein loosens any flavorful bits stuck to the bottom. Scrape them up into your sauce.
1½ bunches rainbow Swiss chard, divided
⅛ ounce thyme, divided
12 ounces butternut squash
2 cloves garlic
3 shallots, divided
8 ounces milk
3 ounces shredded Gruyère cheese
⅓ cup panko breadcrumbs
1½ tablespoons grated Parmesan cheese
½ cup red wine
½ tablespoon butter
¼ cup + 1 tablespoon olive oil
12″ large pan
1 aluminum tin
Preheat oven to 425°F. Rinse chard and thinly slice crosswise, keeping stems and leaves separate. Rinse thyme and set aside half of the sprigs for another recipe, then strip and finely chop leaves of remainder, discarding stems. Halve squash cubes. Mince garlic. Peel shallots, halve, and thinly slice. Pat steaks dry with paper towel.
On a baking sheet, toss chard stems and squash with 1½ tablespoons olive oil, half of chopped thyme, ¼ teaspoon salt and pepper as desired. Arrange in a single layer, transfer to oven, and roast until tender and browning, about 12 minutes.
While vegetables roast, heat 1½ tablespoons olive oil in a large pan over medium heat. When oil is shimmering, add garlic and half of shallot and cook until soft and translucent, about 3 minutes. Add chard leaves and cook until softened, 3 minutes more. Season with ½ teaspoon salt and pepper as desired. Remove from heat and stir in roasted vegetables, ¾ cup milk, and Gruyère. Save remaining milk for your coffee.
Transfer vegetables to aluminum tin, reshaping if bent. Spread in an even layer. In a small bowl, stir together breadcrumbs, Parmesan, remaining chopped thyme, and 1½ teaspoons olive oil. Sprinkle over vegetables. Cover gratin loosely with foil and bake, removing foil halfway through, until cheese is bubbling and topping is crispy, about 12 minutes total.
While gratin bakes, wipe pan from vegetables clean and add 1½ tablespoons olive oil over medium-high heat. Season steaks all over with ¾ teaspoon salt and pepper as desired. When oil is shimmering, add to pan and sear until browned and medium rare, 3-4 minutes per side. Remove from pan and set aside to rest for at least 5 minutes, leaving behind any juices. Once rested, cut steaks against the grain into ¼-inch slices (see Recipe Tip).
While steaks rest, return pan to medium heat. Add remaining shallot and cook until translucent, about 2 minutes. Increase heat to medium-high, then add wine and cook, scraping up any browned bits from bottom of pan, until reduced by half, 2 minutes more (see Recipe Tip). Remove from heat and stir in butter until melted. Spoon pan sauce over steak and serve with gratin.