Spring Egg Drop Soup for Passover; get the recipe, below. (Deb Lindsey/For The Washington Post)

Without eggs, our ceremonial meal would be incomplete — and we couldn’t produce an edible spongecake. Symbolically, they represent mourning, rebirth and the continuity of life, all part of this major Jewish holiday, which begins at sundown on March 30 this year. Passover commemorates the Exodus nearly 3,000 years ago when ancient Israelites broke free from 400 years of slavery in Egypt and, after wandering for 40 years in the desert, were reborn as a nation in the land of Israel.

For centuries since, Jews fulfill the biblical commandment to remember and retell the story of the Exodus with a special ceremony, the Seder. Symbolic foods, including eggs, are part of the story.

It is difficult to pinpoint exactly when a hard-cooked or roasted egg first appeared on the Seder plate, but it was certainly after the destruction of the Temple in Jerusalem in A.D. 70. The egg was added in memory of the special festival sacrifice brought, along with roasted lamb, to the Temple as the Passover offering.

So it became customary in nearly all Jewish cultures that, at end of the Seder and before the parade of dinner food begins, hard-cooked eggs are eaten — dipped in salt water to remember the tears of the ancient Israelites and destruction of the Temple. In my home, Seder guests are served the Sephardic dish called huevos haminados: eggs cooked, uncovered, for long hours with onion skins, peppercorns, a pinch of salt and a layer of olive oil on top. The whites turn a nice light tan shade while the yolks lose their bright color and take on a lovely, creamy texture. Depending on various traditions, some haminados are cooked with vinegar, saffron, coffee grinds and/or purple onion skins in the water.

Beyond the Seder, the egg is at peak performance during Passover: in dishes like the iconic matzoh brei (fried matzoh) as well as in the abundance of baked goods that seem required for a holiday that, ironically, forbids the use of yeast and any food made from wheat, barley, oats, rye or spelt. The ban results from the fermentation and rise that begins when such grains come in contact with water for more than 18 minutes, making them leavened food (“chametz,” in Hebrew) that is not kosher for Passover.

Why does this matter? When the Israelites left Egypt in haste in the middle of the night, there was no time for their daily bread’s overnight rise. Instead, they wrapped up their bundles of dough and carried them into the desert, where the sun and heat baked them crisp and flat. We eat the flat matzoh to mark this festival of unleavened bread.

Passover baking today is a sort of a throwback to when eggs and egg whites were the main way to make food rise. It wasn’t until the mid-19th century that baking soda and baking powder were introduced. Both are now manufactured in ways deemed suitable for Passover, but given the weightiness of nut flours and density of matzoh cake meal, eggs are necessary in savory and sweet dishes.


Mocha Chip Meringues. (Deb Lindsey/For The Washington Post)

The trick with egg whites is to beat the eggs long enough to whip lots of air into the whites, which also changes the shape of the egg proteins to allow for even more air to be trapped. Don’t skimp on this step, and your meringues should be melt-in-the-mouth sweet.

Those yolks left over from making meringues can find a delicious home in egg drop soup. Recipes for it typically call for soy sauce, which as a fermented food is not permitted at Passover. The soup is also often made with chicken broth, but vegetable broth makes an excellent substitute. Whichever broth you like, imbue it with garlic, ginger and a touch of sesame oil for Asian flavor.


Leek and Potato Casserole (Quajado). (Deb Lindsey/For The Washington Post)

There are many varied family recipes for quajado; most are traditionally made of leeks, eggplant, eggs and sometimes cheese. We often use the New World potato instead of eggplant, while leeks, a favorite ingredient of Spain’s medieval Jews who grew it abundantly in home gardens, make the dish. Some people call quajado a frittata, but there is a difference: Quajado has more vegetables, less egg. Some versions for Passover mix in softened pieces of matzoh.

While it might be tempting to use liquid egg whites (sold in cartons) instead of separating eggs into yolks and whites, I have found that they do not whip up quite the same. The problem is that pasteurization of the packaged whites uses a heat process that changes the proteins. Consequently, those egg whites don’t take on air as well, so you need to whip them two to three times longer to get close to the results you want.

I make sure to keep enough eggs on hand, which can mean at least two dozen — and that’s not counting the ones used in all the baked treats and hard-cooked eggs consumed at my Seder. I always cook as many as a dozen extra for my own meals while I make the ones for the holiday table. The extras are then ready for a quick egg salad — one of my favorite matzoh toppers — or on their own for breakfast, lunch or a snack with a squeeze of lemon and some salt and pepper, just the way my father ate them.

Sliced eggs add protein to a salad and, if you’re having company, deviled eggs make a fine Passover appetizer. I will also use eggs to bake holiday treats midweek, and in matzoh brei, of course.

Egg consumption continues a decade-long rise, with estimates that Americans eat more than 270 eggs per person each year. I certainly do my share at Passover.

Barocas is a writer, caterer, teacher and filmmaker in Washington. She will answer Passover cooking questions on Wednesday’s Free Range chat: live.washingtonpost.com.

Recipes:

Leek and Potato Casserole (Quajado)

8 to 10 servings

MAKE AHEAD: The quajado can be refrigerated for up to 4 days. The cooked dish freezes well, for up 2 months. Reheat the defrosted casserole, uncovered, in a 350-degree oven for 15 to 20 minutes, or until heated through.

Ingredients

3 large or 6 medium russet potatoes (about 3 pounds total)

3 tablespoons extra-virgin olive oil, plus more as needed

6 to 7 large leeks (3 to 3½ pounds total)

1 large or 2 medium carrots, shredded (about ¾ cup)

5 large eggs, beaten

1 teaspoon salt (less if using feta or another salty cheese)

½ to 1 teaspoon freshly ground black pepper, plus more as needed

½ cup crumbled feta or shredded hard cheese such as Parmigiano-Reggiano (optional)

Steps

Preheat oven to 350 degrees. Line a baking sheet with aluminum foil.

Scrub potatoes under cold water, then cover lightly with a teaspoon or two of oil using your hands or a pastry brush. Place potatoes on the baking sheet and prick the skin 4 or 5 times with a fork to let out the steam as they cook. Bake (middle rack) for 50 to 60 minutes, until the insides are very soft when pricked with a fork. Alternately, to cut the baking time, cook the oiled potatoes in a microwave on high for 5 minutes before baking in the oven for about 30 minutes, until soft. Once the potatoes are out of the oven, cut in half the long way and open them to cool faster.

While the potatoes cook, clean and prepare the leeks. Cut off the dark green tops and save for making stock. (They can be washed and stored in the freezer until ready to use.) Cut off the roots and discard. Pull off a couple of layers of the tough part of the white and any damaged parts. Split the white of each leek lengthwise, then cut across into half-inch pieces. You will have 8 to 9 cups of leek pieces.

Place the leeks in colander or strainer that fits into a large bowl (or pot) and wash under cold water. Set the colander into the bowl and fill with cold water. Let soak for a few minutes, then swish the leeks around to dislodge any grit. Give the dirt time to fall to the bottom, then lift out the colander or strainer. Toss and mix the leeks, checking for remaining grit. As needed, rinse the bowl and repeat the washing process.

Alternatively, place the leek pieces in a large bowl and fill with cold water. Let sit for a few minutes, then swish the leeks with your hands. Wait a few moments for any grit to fall to the bottom, then scoop out the leeks with a slotted spoon, disturbing the water in the bowl as little as possible. Set the leek pieces aside, rinse the bowl and repeat washing the leeks as needed.

Set a steamer into a pot with a few inches of water in the bottom and bring to a boil over high heat. Place the clean leek pieces in the steamer, cover the pot, reduce the heat to medium and cook for 15 to 20 minutes, until very tender.

Transfer the cooked leeks to a colander or strainer and force out any liquid with the back of a spoon.

Scoop out the insides of the cooled potatoes, leaving a thin layer next to the skin. The yield is about 4 cups. Mash together the leeks and potatoes, breaking up any large lumps. Add the grated carrot, beaten eggs, salt, pepper and the cheese, if using, Stir until well incorporated.

Reheat the oven to 350 degrees.

Use 2 tablespoons of the oil to grease a 9-by-13-inch baking dish. Place in the oven for 3 to 4 minutes, or until well heated, then remove it just long enough to spread the leek-potato mixture in the dish in an even layer. (When the pan is really hot, the mixture should sizzle as it hits the oil.) The heated baking dish and its oil will help create a crust on the bottom and sides of the casserole. Gently brush the top of the leek-potato mixture with the remaining oil. Bake (middle rack) for 30 to 35 minutes, until the mixture is firm and golden brown around the edges.

Serve right away, or cool completely before storing.

Mocha Chip Meringues

Spring Egg Drop Soup

More Passover egg-related recipes:

Poppi’s Spongecake

Sweet Dairy Brunch Kugel

Chocolate Almond Tweed Torte

Mazzagna Verde

Lemon Layer Cake

Puffed Matzoh Meal Pancakes

Passover Popover Rolls

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