Woo! I'm getting crazy with the tarts these days.
This one uses dried lavender, which gives a lovely herbal bite to the sweetness of the caramelized onions. The original recipe used crisped proscuitto as a base (that is, proscuitto sauteed a little bit until crispy), but I used some leftover ham which I thought worked just as well. Other things you might use: country ham, crumbled bacon, or go veggie and use blue cheese crumbles.
I also used the walnut crust from the bacon and chard tart. It's my new all-purpose tart crust.
Loosely adapted from Ancient Grains for Modern Meals:
2 big onions, sliced (I used Vidalia onions)
1 1/2 teaspoons dried lavender
1 teaspoon dried thyme
4 oz proscuitto or ham or bacon or blue cheese or whatever
2 large eggs
1/2 cup plain Greek yogurt
1/2 cup milk
1 oz grated cheese (I used parmesan; gruyere would also be yummy)
1 tablespoon Dijon mustard
Caramelize the onions by sauteing on medium-low, in olive oil or bacon fat, for the better part of an hour. Let them get dark, the darker they are the sweeter they taste. Meanwhile make the tart crust and par-bake it according to the instructions.
Remove the onions, and saute the meat in the same pan with a little more olive oil. In a bowl, mix together the eggs, yogurt, milk, cheese and herbs.
Brust the tart crust with the mustard, layer the meat in the bottom, add the onions. Pour the egg mixture over all that, and bake at 375 for 45 minutes. Let sit for 15 minutes before serving.