Asparagus and Shiitake Mushroom Tart with Polenta Crust

Last month, I had brunch with Deborah Madison. (Ok, there may have been a few other people there, too.)

I’ve been a Deborah fan since I picked up a copy of Local Flavors at the UC Santa Cruz book store during my senior year, and proceeded to shirk my studently responsibilities – trifling matters like papers, homework, and presentations – to make everything from potage to pancakes to pandowdies. Deborah is a fellow Banana Slug, and, due to her success as a chef and writer, I can only imagine that she picked a more useful major than Art History. (Or at least, did her homework.)

Thanks to Jay for being my lovely hand model!

Deborah’s writing style is so calm, warm, and engaging, I feel like she’s been in the kitchen with me for the last 10 years in the form ofVegetarian Cooking for Everyone,Seasonal Fruit Desserts, andVegetable Soups.When I learned that she would be hosting a brunch and booksigning at Left Bank restaurant with dishes from her latest tome Vegetable Literacy, it was with great trepidation that I signed us up (and not just because of the hefty price combined with my inability to find a decent job with an Art History degree). I was still traumatized from the last time I came face to grumpy face with a culinary idol. What if Deborah turned out to a be mean and cranky? How would I ever recover?

Luckily, Deborah was as warm and gracious in person as she seems in her books. I only refrained from hugging her because I didn’t want to get kicked out before drinking the unlimited wine served with brunch. Unfortunately, she left before her biggest (and now drunkest) fan could accost her for a post-prandial photo.

As each lovely course was whisked out by the servers, Deborah said a few words about each. One of the dishes consisted of roasted asparagus spears topped with salsa verde – simple and delicious. Deborah introduced asparagus as “the queen of spring,” a title that I found quite fitting.

Lately, I’ve been especially loving the queen of spring in combination with shiitake mushrooms. Shiitakes have a lighter flavor than most other mushrooms, and their bouncy texture stands up well to cooking, refusing to go soggy like buttons or crimini. Shiitakes tossed with olive oil and salt, then roasted, are particularly addictive, and I have trouble leaving enough in the pan and out of my gullet to put in whatever dish I’m trying to make. I find the pair of them perfectly pitched, and have been enjoying them in citrusy soba salad, creamy penne with goat cheese and herbs, and brothy miso soba noodle soup. But nestled in a polenta crust and surrounded by savory custard is my favorite thus far.

I first saw the idea for a polenta crust on Guilty Kitchen, then The Wednesday Chef(adapted from Ancient Grains for Modern Meals). A quick, thick polenta, enriched with egg, a touch of butter, and parmesan, gets spread in the bottom of the pan, shaped when cool enough to handle, and baked to crisp it up a bit. It’s lighter than pastry, less fussy, and naturally gluten-free. Carey’s beautiful asparagus galetteinspired me to fan out the stalks on top and use greek yogurt in the custard in place of cream. (Also, Carey is my personal hero not only for inventing the awesomest recipes and taking the most stunning photos of them on Reclaiming Provincial, but also for telling off someone who left a rather rude comment on my Bojon Gourmet Facebook page last week. Thank you, Carey!)

I added crumbles of feta cheese and roasted shiitakes to the base. Inspired by Deborah’s love of truffle salt, I splurged on a small jar and added a few pinches to the mushrooms, which lends the tart a touch of magical, mysterious flavor.

The crust holds its shape beautifully, particularly when allowed to set for half an hour post-baking. It’s so easy to make, and so sunny-yellow, I can imagine using it as the base for any savory tart (I bet this roasted eggplant tomato tart would be superb), or even something sweet, with berries, perhaps. The custard bakes up silky smooth and a little bit tangy. And the queen of spring reigns on top, the spears roasting and condensing in the heat of the oven.

It’s a tart that I wouldn’t hesitate serving to Deborah Madison herself (assuming she doesn’t get a restraining order first).

The Queen of Spring:

Asparagus, Leek and Green Garlic Soup
Spring Tabbouleh with Harissa and Grilled Halloumi
Crustless Asparagus Goat Cheese Skillet Quiche

One year ago:

Gluten-Free Espresso Cheesecake Brownies

Two years ago:

Fava Bean and Radish Crostini

Three years ago:

Creamy Sesame Soba Noodle Salad
Rosemary Pine Nut Biscotti

Asparagus and Shiitake Mushroom Tart with Polenta Crust

I used the smaller amount of asparagus here, and thought a little extra wouldn’t hurt. Save the trimmed ends for another use, or cut them into 1/2″ pieces and roast them with the shiitakes, adding them to the tart filling. The truffle salt is optional, but it does add a lovely, magical quality to the tart. (We’ve been enjoying it over pasta and popcorn, too!) Sometimes I add a tablespoon or two of chopped tarragon or chives on top of the mushrooms.

Makes 6-8 light servings

For the crust:
2 1/2 cups water
1/2 teaspoon fine sea salt
1 cup polenta (or yellow corn grits)
1 tablespoon unsalted butter, plus more for greasing the pan
1/2 cup (1 1/2 ounces) grated parmesan
1/4 teaspoon freshly ground black pepper
1 large egg

The vegetables:
6 ounces shiitake mushrooms
1 tablespoon olive oil, plus another tablespoon for the asparagus
a few big pinches truffle salt (or sea salt)
8 – 12 ounces asparagus spears

The custard and cheese:
1/2 cup whole milk Greek yogurt
1 large egg
1/2 cup whole milk
1/4 teaspoon truffle salt or fine sea salt
1/4 teaspoon freshly ground black pepper
1/2 cup (1 1/2 ounces) grated parmesan

3 ounces crumbled feta cheese

Make the crust:
Position a rack in the lower third of the oven and preheat to 400ºF. Grease a 10″ tart pan (or 9″ pie or springform pan) with butter and place it on a rimmed baking sheet. Set aside.

Bring the water and salt to a boil. Add the polenta in a steady stream, whisking constantly. Lower the heat to medium-low and cook, stirring constantly, until the polenta is very thick, 10 minutes. Off the heat, stir in the butter, parmesan and pepper, then stir in the egg. Scrape the polenta into the greased pan, and spread it with the spatula to cool a bit. When cool enough to handle, use damp fingers to form a 1/2″ thick lip around the edge.

Bake the crust until the surface is dry and pale golden, 20-30 minutes.

Prepare the vegetables:
Rinse the mushrooms quickly, dry them on a kitchen towel, and trim off the ends of the stems. Cut the mushrooms into 1/4″ slices and spread on a smallish baking sheet in a single layer. Drizzle with a tablespoon of olive oil and sprinkle with the truffle salt. Toss to coat, then bake them until golden and collapsed, 10-20 minutes. Lower the oven temperature to 375ºF.

Rinse the asparagus spears well. Snap off the woody ends and discard; they will naturally break off in the right place. Trim the head ends into 3 1/2″ lengths (or 3″ lengths is using a 9″ pan). (Optionally, cut the remaining end pieces into 1/2″ lengths and roast them with the mushrooms.)

Make the custard:
Whisk together the yogurt and egg until smooth. Add the milk, salt and pepper, and whisk until combined.

Assemble and bake the tart:
Sprinkle the parmesan over the bottom of the parbaked crust. Top with the crumbled feta, then the mushrooms (and optional asparagus ends.) Pour the custard over, then arrange the asparagus spears in a circle with the heads pointing in. Drizzle the asparagus with the remaining tablespoon of olive oil, and sprinkle with another pinch of truffle or sea salt.

Bake the tart until the custard is set and a knife inserted near the center comes out clean, about 40 minutes. Let the tart cool for at least 30 minutes and up to an hour; this will firm up the bottom of the crust, ensuring clean slices. I like the tart best slightly warm, but not hot.

Store leftovers in the refrigerator for up to three days, and reheat in an oven or toaster oven before serving.