Caramelized Onion and Wild Mushroom Tart with a Hazelnut Crust (Gluten-Free)

Caramelized Onion and Wild Mushroom Tart with a Hazelnut CrustLike many of the recipes that I make up, this one is time consuming; but, I really, genuinely enjoy cooking so I’m never going to skip caramelizing the onions just because it takes so long! Anyway, this is the sort of dish you make for a special occasion, for people who you truly love.  I’m taking it to a tiny New Year’s Eve gathering tonight.  If I have served you a dish that involved caramelized onions you know that I truly love you. Caramelized Onion and Wild Mushroom Tart with a Hazelnut Crust2017 has been a “better late than never” kind of year for me.  I have a accomplished plenty but all of it has been with tinged with the feeling that I should have already had this or that finished long ago! I might be late with my accomplishments, but I have spent many hours caramelizing onions as an expression of love.  I’m ok with that.


  • butter and rice flour for the tin
  • 1 cup brown rice flour
  • 1/3 cup potato starch (not potato flour)
  • 2 heaping Tablespoons tapioca flour (also known as tapioca starch)
  • 1/2 tsp salt
  • 1/4 cup hazelnuts, finely chopped
  • 8 Tablespoons (1 stick) cold butter cut into 8 chunks
  • 1/4 to 1/2 cup milk
  1. Mix the rice flour, potato starch, tapioca flour, salt and chopped hazelnuts in a large bowl.
  2. Use your fingers or a pastry cutter to cut the butter into the flour until it resembles fine bread crumbs.
  3. While stirring, add just enough milk to form a ball.  I usually use a little more than 1/3 cup, but it all depends on how dry your flours and starches are.
  4. Cover the ball of dough in plastic wrap and refrigerate for 15 minutes.  You can start to prep the filling while the dough chills.
  5. Butter and flour a tart or pie tin.  Between two 12 inch sheets of wax paper roll out the pastry until it is large enough to fill your tin.  Remove the top sheet of wax paper and flip the rolled dough into the prepared tart tin.  Carefully remove the top sheet of wax paper and use your fingers to repair any cracks in the crust.  Refrigerate the crust for 30 minutes and continue working on the fillings.
  6. Preheat the oven to 350 and bake the crust unfilled for 20 minutes.  Finish making the fillings while the crust bakes.


  • 2 oz dry porcini mushrooms
  • 1 large or 2 small red onions (about 2 cups sliced)
  • 2 Tb butter, divided
  • 2 Tb olive oil, divided
  • salt and pepper
  • 16 oz fresh mushrooms (I used cremini, but you could go cheaper with white mushrooms or more expensive with oyster mushrooms as you wish)
  • 1/4 cup white wine
  • 1 tsp brown sugar
  • 1/3 cup dried cranberries
  • 1 egg yolk
  • 1/2 cup whipping cream
  • 1/3 cup crumbled blue cheese or gorgonzola
  • salt and pepper
  • 5 oz goat cheese
  1. In a large skillet, heat one Tablespoon of olive oil and one Tablespoon of butter.  Add onions and salt and cook over low heat stirring frequently for one hour.  The onions should become a dark brown, caramelized marmalade.
  2. Meanwhile, soak the dry porcini in about a cup and half of very hot water for 30 minutes.  When they are soft, remove them from the liquid, chop them and set aside.  Strain the liquid through a mesh sieve and to remove grit .  Save the mushroom liquid for later.
  3. While the dry mushrooms are softening and the onions caramelizing, clean and dice the fresh mushrooms.  It is best not to run water over mushrooms to clean them.  Mushrooms are designed to absorb liquid.  They will absorb the water along with whatever bacteria you were trying to rinse off.  Wipe the mushrooms with a paper towel instead.
  4. In another very large skillet, heat the remaining butter and oil.  Add the mushrooms and salt.
  5. When the mushrooms release their liquid, add the softened, chopped dry mushrooms.
  6. When the mushrooms begin to sizzle and brown, add the white wine, brown sugar and dried cranberries.
  7. When the wine reduces by half, add the strained mushroom soaking liquid.
  8. When the mushroom liquid reduced by half, add the caramelized onions and simmer over low heat until very thick.  Taste and season with salt and pepper.
  9. Preheat the oven to 350 degrees.
  10. Combine the egg yolk and cream in a large bowl.  Whip the mixture until it forms soft peaks and put it in the fridge.
  11. Spread the caramelized onion and mushroom mixture into the bottom of the pre-baked crust.  Sprinkle crumbles of the goat cheese and goat cheese on top.  Spoon the cream mixture over the filled tart and use a spatula to smooth it down and make sure that it gets spread all the way to the sides.   Bake the tart for 30 minutes or until the center is set.  Its good hot, warm, room temp or cold out of the fridge a day later.


3 Comments Add yours

  1. Glenda says:

    You love me! ❤️ Happy New Year my kitchen goddess! 🎊

  2. chefkreso says:

    This is such a must-try! Bookmarking the recipe 😀

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