Tantalizing White Onion & Tuna Tart

This is my dinner from last Tuesday.  I’ve been meaning to make this for a long while.  What took so long? Lack of careful planning — when I have the fish, I don’t have the white onions, when I have fish and onions, I don’t have the dough.  Finally, they all came together to my fridge, and so it was the sign that it was time to implement my plan.

The idea behind this is really simple — put together a robust savory tart, and bake a mild-flavored fish in it.  I chose the white onions for two reasons — they tend to be predictably sweeter than yellow onions I typically use in my daily cooking, and they have the robust oniony flavor I was looking for, but without the punch — you could readily make a marmalade out of them — they are just so mellow and silky when fully cooked.

I am very pleased with the outcome.  The only damper on the whole experience was the absence of my husband — he had a meeting that night, and couldn’t participate in the dinner with us, thus missing out on the Big Yum Experience, as we call this in our house.  And though he did get to taste the pie after he came home (the pie was still warm), he certainly missed out on that flaky delicate crunch one gets when the puff pastry is freshly baked.  As a side note, the pie was still pretty darn good the next day for lunch (without the crunch).

Tantalizing White Onion & Tuna Tart

• 2 sheets of ready-made frozen puff pastry, thawed according to instructions
• 2 generous tbsp butter
• 3 large white onions, peeled, halved, and sliced thinly
• 3 large eggs
• 1 cup cream
• salt and freshly ground black pepper to taste
• pinch of freshly ground nutmeg
• pinch of sweet Hungarian paprika (optional)
• 1/2 cup fresh ground mild flavored cheese, such as gruyere, asiago, or mild cheddar
• 1 lbs of mildly flavored fish fillets, I used wild tuna, cut into 1/2″ thick chunks

1. Cut fish into 1/2″ thick slices (if it’s not already). Sprinkle salt and fresh ground black pepper liberally all over the fish, and set aside.
2. Melt butter in a Dutch oven over medium heat
3. Add the onions and saute for a few minutes, until they become translucent. Be sure not to brown them in any way.
4. reduce heat to very low, cover the Dutch oven tightly, and cook onions for about 20 minutes, stirring once or twice to prevent browning. Onions should be fully flavored, lightly yellow, but not brown, and most of the onion juices should be gone. If this state isn’t reached in 20 minutes, cover and cook longer, checking every 5 minutes for doneness.
5. Whisk the eggs and cream together
6. Remove onions from heat, add egg and cream mixture and stir very thoroughly, until creamy and uniform.
7. Season with salt and pepper to taste, add nutmeg.
8. Finally, add the cheese and stir gently to distribute.
9. Add paprika if desire.
10. Sprinkle the surface of the table with flour lightly
11. Roll out puff pastry to be slightly larger than the baking pan (I used a 10″ pie pan).
12. Line the baking pan with the layer of puff pastry, press it into the sides of the pan to form a pie shell.
13. Pierce the shell all over with the fork
14. Fold out half of the egg and onion mixture into the baking pan
15. Arrange the fish slices over in a single layer, covering the entire surface of the pie
16. Fold out the other half of the egg and onion mixture over the fish layer
17. If you wish to make patterns in the pie, make them at this time. I improvised and used a plastic cap of a water bottle to cut out incomplete circles in the crust. While baking, the circles puffed out and shrunk, creating little peek-a-boo openings in the pie.
18. Carefully transfer the top pie crust onto the top of the pie. Stretch out if necessary to distribute your patterns nicely.
19. Using a rolling pin, press the pie crusts together to the rim of the baking pan, thus cutting the extras off without stretching the crusts.
20. Bake for about 30 minutes at 425°F, or until the egg and onion mixture is set in the middle, and pie crust is golden and flaky.