Spinach and Onion Tart

Preparation

1. Step 1

   Preheat the oven to 350 degrees. Oil a 10-inch tart pan and line it with the pastry. Keep it in the refrigerator while you prepare the filling.

2. Step 2

   Steam the spinach above an inch of boiling water for 2 to 3 minutes, until wilted. You will probably have to do this in batches. I like to use a pasta pot with an insert for steaming spinach, as I can get a lot of it into the insert. Rinse briefly with cold water, squeeze out excess water and chop medium-fine.

3. Step 3

   Heat the olive oil over medium heat in a large, heavy skillet and add the onion. Cook, stirring often, until it is tender and beginning to color, about 8 minutes. Add the spinach, thyme and salt and pepper to taste, and stir together. Remove from the heat.

4. Step 4

   Whisk the eggs in a large bowl. Add salt to taste (I use about ½ teaspoon) and whisk in the milk. Stir in the onion and spinach mixture and the cheeses. Scrape into the pastry-lined tart pan. Place in the oven and bake 40 to 45 minutes, until tart is set and beginning to color on the top. Remove from the heat and allow to cool for at least 15 minutes before cutting. Serve warm or room temperature.