We tend to eat at least seventy-five percent vegetarian during the week, yet for some reason when I entertain on the weekends, I often feel obligated to serve up a big slab of meat. It might be a roast chicken, filet of salmon, or lamb curry, but seldom is it vegetarian fare.
As I was assembling this mushroom and polenta gratin, I wondered to myself why I always chose a protein as my main dish and why didn’t I indulge my friends in some of the healthier and more adventurous dishes that we eat day to day?
Whatever the reason – expectations, tastes or tradition – it became apparent as I dished up this gratin around our dinner table that I had created something well-worth sharing. Meat-lovers, or no meat-lovers.
This leek and mushroom bake with its polenta-Parmesan crust more than holds its own as a main dish – it steals the show. Aromatic leeks and no-nonsense celery are paired with woodsy, garlic-sauteed mushrooms to form the base of the bake. They are topped with a smooth Bechamel (a basic white sauce) that has been jazzed up by a handful of sharp Parmesan. The final layer is thin cakes of cooked and cooled polenta and everything is topped with more cheese.
As our creation bakes, the mushrooms and leeks perfume the dish and the polenta bubbles into a lovely crust. It is then ready to be spooned up alongside more seasonal vegetables for a perfect autumn meal.
Do-Ahead Tips and Ingredient Sourcing
Most vegetarian dinners come together so simply that it would be easy to glance over this recipe and think “Now why would I ever bother with four steps?” but this recipe is special. I think even holiday dinner special – especially if you’re hosting a few friends and family who skip the Christmas ham and Thanksgiving turkey.
Another reason why I’m sharing this dish is because it can easily be broken down into manageable steps that can all be completed one or two days in advance. In fact, once the whole shebang is assembled, it can hold for 24 hours, refrigerated and sealed in plastic wrap, until it is ready to be baked off and served piping hot.
Do ahead? Check.
Step-by-step? Yes, indeed.
So what about those funky ingredients, then? Well, if you are accustomed to preparing vegetarian main meals, you probably are already familiar with dried mushrooms and polenta, not to mention whole leeks. But in case those sound a little frightening, here’s a quick schooling.
Polenta ~ You’ve probably spotted beautiful bright yellow polenta in the bulk food section of your organic store already. It might even be labeled as cornmeal, as it is essentially the same thing. For our breakfasts, I buy the quick cooking cornmeal, but for this recipe (and if you’re ever cooking and cooling polenta to grill) select the coarse polenta.
Dried Mushrooms ~ Chosen for this dish because of their high concentration of flavor, dried mushrooms play the star role of the gratin and provide a ‘meatiness’ that gives the dish a well-rounded, nourishing feel. Fresh mushrooms just wouldn’t provide the same texture, plus I’m always looking for ways to use up the dried wild mushrooms that my mother sends me.
Look for dried mushrooms such as shiitake, morels, and porcini at your health food store or farmer’s market. You can also find them for purchase online.
Leeks ~ One of my favorite winter vegetables is the humble leek. I featured it last year as a Spotlight Ingredient, where you can read all about buying, storing and cleaning the leek. The subtle flavor of the leek lends itself to a beautiful pairing with the mushrooms in this bake and shouldn’t be replaced with onion. So go ahead and buy and bundle. You can always make this or this soup with the remaining stalks.
Parmesan ~ I always have a chunk of this firm Italian cheese in my refrigerator – and the real stuff, too. It is expensive, but a little goes a very long way in the flavor department. You could also substitute Pecorino Romano in this dish, or, in a pinch, sharp cheddar. You can find Parmesan at almost any grocery store, although I go out of my way to purchase it from an Italian grocer because it costs much less.
Recipe: Leek & Mushroom Bake with Polenta-Parmesan Crust
Serves 6 as a main dish, 8-10 as a side dish.
- 3 ribs celery
- 2 leeks, white part only
- 1 Tablespoon olive oil
- 1 Tablespoon butter
- 2 cloves garlic, peeled
- 2 cups dried mushrooms (I used shiitake and morels)
- 1 recipe polenta crust
- 1 recipe Bechamel sauce
- 1/2 cup grated Parmesan cheese
Step 1: Polenta Crust
- 1 1/2 cups coarse polenta
- 6 cups water
- 1 teaspoon salt
- 2 tablespoons butter
- Bring water and salt to a boil in a heavy bottomed sauce pot. Over medium heat, whisk polenta into boiling water, a handful at a time, until it is all incorporated.
- Reduce heat to medium-low and cook polenta, stirring frequently, for about 30 minutes. It will become quite thick. Tip: While your polenta is cooking, prepare steps 2 and 3 of this recipe.
- Remove polenta from heat and beat in butter. Pour onto a buttered baking sheet and spread out with a spatula into a rough 9×13 rectangle. Polenta will be moldable.
- Cover with plastic wrap and refrigerate until firm or up to two days.
Step 2: Roasted Vegetables & Sauteed Mushrooms
- Preheat oven to 400°F and lightly oil a baking sheet or roasting pan.
- Wash and dry celery and leeks. Slice leeks into 1/4 inch ‘coins’. Chop celery ribs into 1/4 inch pieces also.
- Place vegetables in a single layer on the baking sheet and roast in the oven for 15 minutes. Give the pan a shake and rotate it at least once during the cooking process.
- Soak mushrooms in warm water for 20 minutes (Tip: you can make your Bechamel sauce during this time).
- Melt 1 tablespoon butter in a medium sauce pan. Bang garlic cloves with the flat side of a knife to bruise them and toss them into the butter.
- Drain mushrooms, squeezing out as much liquid as possible, and add them to the garlic butter.
- Season mushrooms with salt and pepper and cook over medium heat for about 7 minutes.
Step 3: Basic Bechamel Sauce
- 3 Tablespoons butter
- 1/3 cup all-purpose flour
- 2 1/4 cups milk
- 1/2 teaspoon salt
- Melt butter in a medium pan or sauce pot over medium heat. Dump the flour in all at once and whisk to combine. Cook, stirring constantly, for about two minutes to develop a little more flavor and avoid a ‘floury’ taste in your bechamel.
- Gradually add in the milk, whisking vigorously to emulsify sauce and eliminate lumps. Once all the milk has been added, bring to a slow boil and stir until thick and smooth.
- Season with salt to taste and reserve until ready to use.
Step 4: Assembly and Baking
- Preheat over to 350°F and butter a 9×13 baking dish.
- Combine roasted celery and leeks in the dish and spread out to cover the bottom in a single layer. Top with the sauteed mushrooms, uniformly scattered throughout.
- Pour bechamel sauce over the vegetables and distribute evenly using a rubber spatula. Sprinkle with 1/4 cup grated Parmesan cheese.
- Cut chilled polenta into rectangles and arrange on top of the bechamel. Sprinkle with remaining 1/4 cup of Parmesan cheese.
- Place dish in oven and bake, uncovered, for about 40 minutes, until top is browned and the bechamel is bubbling up the sides.
Serve at once.
What is your favorite vegetarian main dish?