Savory Asparagus Tart with Mustard, Caramelized Onions, Lemon, and Tomme

This asparagus tart is a springy riff on the potato tart that I made at the farm late last summer. Then, I was working with a wheel of goat tomme that Arlene had made, but this time I was lucky enough to use a hunk of the cow tomme that I made in the fall with my very own shaky, inexperienced hands. After letting four wheels age a full five months in the cave, we finally cut one open late last week, and it tasted dang delicious. I was shocked. The black stripe of vegetable ash—made famous by Humboldt Fog—isn’t traditional to tomme-style cheeses, but it gave this wheel some beautiful character and a deep, delicious saltiness that made it a lovely candidate for baking.

Even so, don’t let the specialty cheese sway you from baking your own version of this tart. Any sort of semisoft or hard cheese would do, from gruyère to sharp cheddar, or even ricotta salata. And although this recipe uses a cow’s cheese, a hard goat’s or sheep’s cheese would be so at home with the asparagus and caramelized onion. On a more personal note, I also really enjoyed making this because it reflects two very important seasons in my life: the momentum of spring now and ahead, and my formative fall at the farm. Special to make, special to eat—it really had no choice but to be good.

Olive Oil Press-In Crust

I like to use this olive oil crust when I’m baking for my butter-wary parents. Feel free to substitute your favorite buttery pastry dough, such as this one.

1 1/2 cups all-purpose or pastry flour

Heaping 1/2 teaspoon flaky sea salt

1/4 teaspoon baking powder

1/3 cup olive oil

3 to 5 tablespoons cold milk or water

1. Combine all the dry ingredients in a medium bowl. Pour olive oil and first three tablespoons of milk in, and whisk with a fork until mixture is evenly blended and somewhat moist. If need be, add an extra tablespoon or two of milk to get moist, crumbly consistency.

2.  Press dough crumbles into an 8- or 9-inch tart pan, using a metal measuring cup to ensure even edges that are flat against the bottom and sides. Pop into the fridge while you prepare the filling.

Savory Asparagus Tart

Makes one 8- or 9-inch tart

1 pound asparagus, from about one bunch

1 large yellow onion, sliced into thin rings of half-moons

1 tablespoon Dijon mustard

¾ cup heavy cream or half-and-half

1 large egg

Zest of half a lemon

½ teaspoon flaky sea salt

1/3 cup grated hard cheese such as asiago, gruyere, or tomme (I used farm-made cow tomme!)

Olive oil

Pinch red pepper flakes

Cracked black pepper

1.  Preheat oven to 350 degrees F.

2.  Caramelize onions: heat a medium, heavy-bottomed saucepan for two to three minutes over medium heat until it’s quite warm. Turn heat all the way low, and add onions to the dry saucepan. Stir for about two minutes, then cover, and leave to cook for 15 to 20 minutes, checking occasionally and stirring onions as needed. By this point, they should smell sweet and be browning evenly. Add a tablespoon or so of olive oil and a pinch of salt, and, stirring every few minutes, continue to cook uncovered for another 15 to 20 minutes until the onions are very dark brown. Remove from heat and set aside.

3.  Cook asparagus: fill a medium saucepan with water and bring to boil. Snap off all of your woody asparagus ends, and boil the spears for just one minute. Drain immediately and run under very cold water to stop the cooking. Pat asparagus dry. Heat two tablespoons of olive oil in a medium saucepan and when it’s hot, add asparagus. Top with a few pinches of red pepper flakes and a small pinch of salt, and allow asparagus to brown for about five minutes. Flip, and cook the other side for another five minutes. Remove from heat and set aside.

4.  Assemble and bake:  whisk the egg, cream, zest, and salt in a small bowl and set aside. Retrieve your tart crust from the fridge, and spread the mustard across the bottom (an offset spatula makes this easy). Arrange onions in an even layer across the bottom, then top with asparagus spears. I lined mine up tightly and side to side like soldiers across the whole tart, alternating tops and bottoms, then tucked the remaining spears into the bare shoulders of the pan. Pour cream mixture over the top of tart, then top evenly with cheese. Crack some black pepper over the top, slide onto a cookie sheet, and bake for 45 minutes until tart is evenly browned. Allow tart to cool for 15 minutes before removing from pan. Cut slices with a very sharp knife—leftovers will keep for about three days.