Red Onion and Walnut Tart

April 13, 2016

blog.krissyosheaphotography2016-4 blog.krissyosheaphotography2016-7It is said that necessity is the mother of invention and in the case of this recipe, that is exactly what happened.

This invention was born on one of those days of one of those weeks. A white rabbit sort of a week. The kind where you spend the whole week rushing around never knowing quite what day it is and perpetually shouting, either into the phone or just in your own head, “im late! im late”

And then comes Friday, and all you want to do is sigh a great sigh of relief and relax, perhaps pour a little glass of red wine and have something which feels very decent and indulgent on the table.

And this is where the recipe for this Red Onion and Walnut tart was born. On a spring-ish sort of Friday evening at approximately 6:30pm. Disregarding the completely upturned house behind me, the long trail of coffee mugs leading between my desk and the kitchen, and turning a blind eye to the whole general disarray, I turned instead to the pantry. If my week was of the white rabbit sort, my Friday night was more the Old Mother Hubbard variety – two  little heads of radicchio in the fridge, no other fresh vegetables in sight, a huge hunk of hard Parmigiano Reggiano, half a ball jar full of walnut pieces, a crush of red onions left from last weeks farmers market and more eggs than anyone could possibly image. The hens have been quite prolific these last few weeks.  Other than these few bits, the cupboard was pretty bare.

So I opened a bottle of lovely rich, velvety Barbera and immediately started drifting off into memories of trips to Italy. Thinking of course of the beautiful foods I have had there over the years. The tender egg pastas and the plethora of decadent sauces I have had to accompany them. Nibbling on a bit of the hard Parmigiano cheese and savoring the lingering fruit from the Barbera, an idea for dinner materialized.

So a few humble ingredients pantry staples, mixed together, made for one of the most elegant meals in recent memory. And, waiting for the onions to cook was the perfect excuse to sit down together and enjoy another glass of wine and a bit more cheese.

blog.krissyosheaphotography2016We let the onions cook until they were sweet and lovely and very soft. Almost all of the moisture had gone out of them and they had a deep rich hue and nearly candy like consistency.  Admittedly, a few spoonfuls of the onions made their way onto a couple of crackers and were heaven with our Parmigiano –

Let the tart itself bake until the rich eggy center is just set – it will keep the tart light and fluffy.
We ate it warm from the oven with just a bit of shaved radicchio for a salad. I made a really light dressing to go over the radicchio – a bit of honey, lemon juice, olive oil and salt.


Red Onion and Walnut Tart


for the crust

  • 1/2 stick of very cold butter
  • 1/2 cup whole wheat flour
  • 1/2 tsp salt
  • 1 tsp sugar
  • 3 -4 tablespoons ice-cold water

for the tart

  • 4 large red onions
  • 1/2 cup chopped walnuts
  • 8 eggs
  • 3/4 cup plain natural yogurt
  • 1 cup white wine
  • 1 Tbsp raw cider vinegar
  • 5 bay leaves (fresh or dried)
  • 12 fresh thyme sprigs
  • 1 Tbsp sugar
  • pinch of salt
  • 2 Tbsp olive oil
  • 1 Tbsp butter
  • 1 Tbsp water
  1.  add the flour, sugar and salt to a bowl and mix well
  2. cut the butter into very small cubes and add about half to the dry mixture. toss well to coat with flour and then add the remaining butter
  3. begin to rub butter into mixture with fingertips. continue until butter is well incorporated into the dry mixture. you shouldn’t see the butter cubes and the mixture should have the consistency of a wet corse sand
  4. make a little well in the middle of the mixture and add 1 Tbsp of ice water – incorporate with a gentle mix of your hand – add more water as necessary until the dough just stays together in a ball – this will likely be 2 to 2.5 Tbsp of water but you may need more or less depending on your flour
  5. turn the ball out onto a lightly floured board and form into a roughly disc shape
  6. wrap in parchment paper and then again in a lightly damp tea towel  put in the refrigerator to chill for a minimum of 30/35 minutes. The dough can be made a day or two in advance but make sure it is wrapped well so it doesn’t dry out

for the tart mixture

  1. while the dough chills. slice the red onion very thinly into circles
  2. heat olive oil and butter in a large skillet until the butter is melted
  3. add the bay leaves and thyme sprigs and saute until fragrant. approx 2 minutes
  4. add the onions and stir to coat in the butter and oil mixture. saute over high heat for about 3 minutes or until the onions begin to wilt
  5. reduce the heat to medium high and add the salt and sugar. stir through. The onions should begin to reduce some liquid at this point, if not you may need to add a pinch more salt.  Stir often until the liquid has evaporated and onions are very tender. approx 10 minutes
  6. add the white wine to deglaze the pan – then add the apple cider vinegar. reduce heat to low and simmer gently for approx 40 minutes or until the onions are very soft and sweet and all of the liquid has been absorbed
  7. remove the pastry from the refrigerator and let it warm up about 8 minutes or until its soft enough to roll out.
  8. on a lightly floured work surface, start from the center of the disc and gently roll out the pastry crust out . I try to aim for about 1/8 inch. take care not to overwork the dough and go slowly
  9. once the crust is roll, gently lift it into a lightly oiled tart pan, with removable bottom. carefully press the dough down the sides and into the bottom edges of the pan. once this is done, trim the edges neatly and prick the bottom with a fork
  10. place a sheet of parchment over the dough and pour in pie balls. blind bake the crust at 410 for about 10 minutes taking care not to let the edges burn
  11. turn our oven back to 350
  12. remove the dough from the oven and let stand about 10 minutes
  13. in a large bowl, whisk together the eggs, water and yogurt.
  14. discard the thyme sprigs and bay leaves from the onion mixture and spread it evenly on the bottom of the tart crust. Next add the cup of chopped walnuts. finally pour the egg mixture into the tart crust and sprinkle with a few more fresh thyme leaves.
  15. return the entire thing to the oven and bake at 350 for about 20 minutes or until the center is set
  16. remove from the oven and set to cool. It can be served immediately or cold

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