Mushroom Walnut Tarts with Caramelized Onion

Mushroom Walnut Tarts with Onion

Where do you get your motivation for creativity? Did you answer pasta? Can a bowl of bucatini be inspirational? Well, I think so. In fact I’ve done some of my best thinking while slurping noodles. I’ve laid the plans for a remodeled bathroom while lingering over linguine. I never watch presidential debates without pappardelle (well, almost never). And I’m constantly stealing flavor combinations for everything from burgers to pies from the world’s greatest pasta producers. These Mushroom Walnut Tarts with Caramelized Onions were inspired by (you guessed it) pasta.

Could I take the flavors from a well-loved mushroom walnut pasta dish from Suzanne Goin and turn it into something else – like say a tart?

Well yes and no.

Mushroom Walnut Tarts

My first attempt at making these Mushroom Walnut Tarts led me to wet, weepy mushrooms that did not sit nicely on puff pastry. I think that’s why most mushroom tarts use pre-roasted or pre-sautéed mushrooms, or revert to an old-fashioned mushroom cream sauce plopped on pastry.  While these directions can be delicious, they’re hardly groundbreaking.

Ms. Goin’s pasta is very unique. She pairs chewy (charred on the outside but barely cooked on the inside) mushrooms with sweet caramelized onions and well-browned walnuts. If found the dichotomy of textures to be addicting. I was also inspired. I decided to develop a tart that reflected these flavors and textures.

The taste part of the equation seems rather straight-forward – caramelized onions and toasted walnuts. However, the texture of the mushrooms is more difficult to emulate. As I said, raw mushrooms arranged on puff pastry and baked in a blazing oven leads to a culinary fail.

I could have dropped this whole Mushroom Walnut Tarts experiment right there. After all, I rarely (well, never) post my failures. I prefer to pretend they never happened.

Wine Pairing

Château Tour Peyronneau Saint-Émilion Grand Cru
I’ll admit it, I like to bargain hunt and I’m also somewhat fond of wine. So when my iPhone alerts me that wine discounters like Last Bottle, Woot or Wines Til Sold Out has a new deal I just have to check it out. It’s all in the timing. Since I knew I’d be starting my Bordeaux class at […]
Ken Eskenazi

Price $23 (WTSO) — $75 (retail)

Pairs well with beef, lamb, pork, duck, pasta, mushrooms and fresh herbs, cured meats, grilled or smoked foods.

However, my partner Ken is starting a class this week about the wines of Bordeaux. Bordeaux is a French wine region gathered along the banks of the Gironde estuary, and the Garonne and Dordogne rivers. Being the largest fine wine region in the world, there’s quite a bit of wine lore to literally drink up. I figured if Ken can master 57 appellations in one semester the very least I can do is figure out how to keep mushrooms from weeping all over a tart’s crust.

The good news is that failures can be inspirational too.  Which is something that has taken me seven years of blogging to learn.

You see I started this blog because thought I was a pretty good cook. All these years later that statement seems naive – at least knowing what I know now. These days I blog not so much to share what I think I know, but to learn the things that I didn’t even know I didn’t know. One of the things I didn’t know, but learned for this post, is that blanching mushrooms in boiling water causes them to loose enough moisture that they can be sliced and set upon a tart without weeping during baking. It seems counter-intuitive, but (as I’ve learned) many of the best kitchen tricks are. In fact did you know that soaking eggplant in water before you fry it keeps it from getting soggy? Well, it took a couple of fried eggplant failures before I learned that this too is true. GREG

Blanched MushroomsBlanched MushroomsMushroom Walnut Tarts with Onion

Mushroom Tarts with Walnuts and Caramelized Onions 

Print This Recipe Total time Yield 8Source Adapted from Jean-Georges VongerichtenPublished
Mushroom Tarts with Walnuts and Caramelized Onions


  • 1 cup walnuts
  • 2 (10-inch) puff pastry sheets
  • 3 tablespoon unsalted butter
  • 2 onions (peeled and cut into ½‑inch slices)
  • salt and pepper (as needed)
  • 3/4 pound baby bella mushrooms (or similar, stems trimmed)
  • 3 tablespoon olive oil
  • chopped chives (as garnish)


Preheat the oven to 375°. In a pie plate, bake the walnuts for about 8 minutes, or until lightly browned, then let cool and coarsely chop. Line a baking sheet with parchment paper, set aside.

Lay the puff pastry sheets on a lightly floured surface and cut out eight 4‑inch rounds about 1/8 inch thick. Transfer the rounds to the prepared baking sheet and prick all over with a fork. Cover with another sheet of parchment paper and set a baking sheet on top. Bake the pastry for about 25 minutes, or until it is cooked and lightly browned; remove the pastry from the oven, take off the top baking sheet and discard top piece of parchment. Set rounds aside. Increase the oven temperature to 425°.

Meanwhile, melt the butter in a large skillet set over medium-high heat. Add the onions and a pinch of salt. Cook, stirring constantly for about 4 minutes; then bring the heat to low and cook, stirring often, until golden and jammy, about 55 minutes. Set aside a few moments to cool then, using a food processor, coarsely puree the onions with the toasted walnut pieces. Season lightly with salt and pepper.

Bring a medium saucepan of water to a boil. Add mushrooms and blanch until just tender, about 2 minutes. Drain, pat dry and slice ¼ inch thick.

Spread the pastry rounds with the onion/walnut puree and arrange the mushroom slices, overlapping, on top. Choose the best looking slices as you might not use them all. Brush tops with olive oil and bake for 12 to 15 minutes, or until the edges begin to brown. Garnish with chives and serve.