Gruyere Spinach Au Gratin with Sherry-Glazed Mushrooms
Squeeze every drop of water from the spinach and sear the mushrooms hard before deglazing with sherry — those two moves are what keep the Gruyère Mornay glossy instead of watery. Bake it all under a Parmesan crust and you have a steakhouse creamed spinach with genuine depth, worthy of the head of the table.
Creamed spinach earns its dated reputation from a single, avoidable flaw: water. Spinach holds an astonishing amount of it, and left unaddressed, that moisture thins the cream sauce into something pale and weeping. Correct for it — and add the savory weight of sherry-glazed mushrooms — and the dish transforms into the rich, glossy, deeply savory gratin you'd expect beside a great steak, not the sad spoonful of memory.
Squeeze the Spinach Dry
This is the non-negotiable step. Whether you start with thawed frozen spinach or freshly steamed, press it in a fine-mesh colander — with your hands or heavy paper towels — and wring out as much water as you physically can. That residual moisture is precisely what breaks a rich cheese sauce, so the drier the spinach, the more the Gruyère Mornay can cling to it in a thick, luxurious coat rather than sliding off into a puddle.
Searing and Deglazing the Mushrooms
The mushrooms bring the umami backbone, and they need real heat to deliver it. Lay them in a single layer in a hot, foaming pan and leave them undisturbed until they're deeply golden on the bottom before tossing — crowding or stirring too soon just steams them gray. Once browned, deglaze with dry sherry, scraping up the caramelized fond and letting the liquid cook away entirely, so all that concentrated flavor stays in the mushrooms and none of it waters down the dish.
Gruyere Spinach Au Gratin with Sherry-Glazed Mushrooms
Ingredients
Method
- If using frozen spinach, thaw completely. If using fresh, steam 2 pounds of spinach until fully wilted.
- Place the cooked spinach into a fine-mesh colander. Using your hands or heavy paper towels, aggressively press and squeeze out as much moisture as physically possible. (This critical step prevents the residual water from breaking the rich cheese sauce during the bake). Transfer the dry spinach to a large mixing bowl and set aside.
- Heat the 2 tablespoons of olive oil and 2 tablespoons of butter in a large skillet over medium-high heat until foaming.
- Add the sliced mushrooms in a single, even layer. Do not stir immediately; allow them to sear undisturbed until deeply golden brown on the bottom, about 4 to 5 minutes.
- Toss the mushrooms to brown the second side for 2 minutes.
- Reduce the heat to medium and pour in the dry sherry to deglaze the pan, scraping up the caramelized fond. Cook until the liquid completely evaporates, about 3 minutes. Season with kosher salt and black pepper, then remove from heat.
- Preheat the oven to 375°F.
- In a medium saucepan, melt 2 tablespoons of butter over medium heat. Whisk in the flour continuously for 1 minute to cook out the raw starch and establish a pale roux.
- Slowly stream in the whole milk, whisking constantly until the sauce is completely smooth and begins to bubble and thicken, about 5 minutes.
- Remove from heat. Whisk in the ground nutmeg and the freshly grated Gruyere cheese until completely melted into a glossy, thick sauce.
- Pour the hot Gruyere sauce directly over the dry, squeezed spinach in the mixing bowl. Stir vigorously until the spinach is thoroughly coated and suspended in the cheese sauce.
- Transfer the creamed spinach mixture into a shallow ceramic au gratin dish (or individual ramekins).
- Layer the sherry-glazed mushrooms evenly over the top of the spinach.
- Scatter the grated Parmesan cheese heavily across the mushrooms. Dot the surface with the remaining 1 tablespoon of butter (cut into tiny pieces) and finish with a light dusting of paprika.
- Bake in the preheated 375°F oven for 10 to 12 minutes, until the casserole is bubbling violently at the edges and the Parmesan crust is deeply golden brown. Serve immediately.
The Heart of the Table
Certain side dishes exist to signal that an occasion matters — and a bubbling gratin of creamed spinach and glazed mushrooms is squarely one of them. It is celebratory food, the kind that turns a good roast into a proper feast and tells everyone at the table that tonight was worth the extra care. Generosity, here, tastes like Gruyère and browned butter.
The Art of the Host
A fine-mesh colander is quietly essential — it's what lets you wring the spinach truly dry. Beyond that, a large skillet sears the mushrooms, a saucepan builds the Gruyère Mornay, and a shallow ceramic au gratin dish (or individual ramekins for a dinner party) takes it into the oven and onto the table under its golden crust.
Neighborly Grace
- The Preparation: Squeeze every drop of water from the spinach and sear the mushrooms hard before deglazing with sherry — those two moves keep the Gruyère Mornay glossy, not watery. Assemble ahead and bake under the Parmesan crust just before serving.
- The Pour: A dry sherry echoes the mushrooms, and a glass of white Burgundy flatters the Gruyère. For a non-alcoholic option, a sparkling grape or a thyme-infused sparkling water keeps it elegant.
- The Vibe: This is steakhouse creamed spinach elevated — rich, glossy, and browned on top, it belongs beside a roast or a holiday centerpiece, spooned out while bubbling.