Alsatian Onion Tart

Making French Onion Soup a couple weeks ago reminded me how fun it is to make an entire meal out of a bag of onions. While cleaning out my fridge and wondering what to do with some ancient vegetable shortening, I remembered the onion tart I learned to make in my French Bistro Classics cooking class.


I made the pastry dough in my food processor using a 3 : 2 : 1 (flour : fat : water) ratio: 2 cups (whole wheat) flour (note: whole wheat: not the tastiest pastry maker in town), 1 cup fat (1/2 cup butter and 1/2 cup vegetable shortening) and 1/2 cup water. Throw in the chunks of cold butter/shortening, fill with the flour, and pulse, while pouring a stream of the water through the hole on top. Do this until it just comes together to form a dough; knead once or twice; wrap in plastic and freeze until you need it.

When you line the tart pan (with removable bottom) with the dough (and no need to butter it; there's enough butter in the dough), it's best to then refrigerate it for a half hour before blind baking (which will be for 15–25 minutes at 400°F).


I docked the dough with fork holes prior to blind baking.


But I didn't do it well enough, evidently.


Fresh sliced onions!


30–45 minutes later: caramelized onions. Once they got going, I had to add drops of water every minute or so to deglaze the bottom of the pot and keep the onions from burning. I used 3 onions for this recipe; next time I'll use 4 or 5. It's amazing how much they shrink.

Once I felt they were sufficiently browned, I sprinkled in 2 Tbsp flour and tempered in 1/3 cup milk (it's possible I should have done this earlier). This was then to be brought to a simmer, then cooled. Though there wasn't quite enough liquid for a visible simmer.


Fill your freshly blind-baked tart shell with the onion mixture, and bake at 350°F for another 10 minutes or so.


BY THE WAY. When you eat a whole bunch of caramelized onions, you need something acidic to cut through the soft sweetness so that it doesn't overwhelm you. I made a tomato onion salad with a simple dressing: olive oil, lime juice, raspberry wine vinegar, dijon mustard and thyme.

I am always forgetting the measurements for making homemade salad dressing. So I will write it here for later reference: 3 Tbsp oil; 1 Tbsp acid (balsamic/red wine vinegar, cider, juice of 1/2 lemon, etc.); 1/2 tsp dijon mustard; honey to taste if needed; herbs, salt & pepper, etc. to taste. The basic equation I learned in cooking class was: 3 parts oil + 1 part acid + Yum (mustard, herbs & spices, frozen fruits, etc.)


There you have it. This meal was brought to you by random ingredients that you probably already have. Just sitting around, waiting to be whipped into onion tart-shape.