Summer zucchini sandwich

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Recipe by Paul Osher
Photos by Annie Lalish

This sandwich’s star is the zucchini. At farmers markets, during the height of summer, you can find a variety called Costata Romanesco, with speckled skin and conspicuous ribs. The flavor is sweet and a bit nutty, and I think the zucchini really personifies the difference between what you find at a farmers market and the supermarket. The supermarket zucchinis are too often used for filler because of their mild flavor and soft texture. But Costata Romanesco zucchinis deserve more. I like the ones grown by One Leaf and Skylight farms in Snohomish.

The supporting cast is more subtly summer. Escarole is a slightly bitter chicory that first peaks in the Pacific Northwest in early summer, and then again in the fall. Like your best friend, escarole complements and brightens any situation. A few years ago, Rand Rasheed, founder of One Leaf Farm, pushed some escarole on me, and I’ll be forever grateful. I love it barely wilted and tucked into nearly any of the food groups: pasta, pizza, bowls, or sandwiches. 

Yes, eggs are available year-round. But they’re especially right in early summer, when the sun shines for long hours and the heat hasn’t yet seeped in. My friend Petrina Fisher, co-founder of Skylight Farms, raises some of the best eggs I’ve ever had. In the summer, the yolks are particularly dark and rich, and the shells are so thick you might need a chisel. Eggs are fantastic seasonal eating, and they push this sandwich over the top. Like with the zucchini, please use the best you can find. Pastured eggs provide the opulence for this simple sandwich in a way that pale supermarket eggs just cannot.

Finally, the aioli. If you’ve never made it by hand before, keep in mind that it takes patience and muscles. It might break as you’re mixing it. That happens to me all the time. But even if it does, the result exceeds the sum of its parts: rich, creamy, garlicky, and not at all sweet or waxy like the stuff in the jar.  

Some might say that early summer is for those glamorous luxuries like cherries, morels, or Copper River salmon. And it might be. But please don’t forget the pleasures of a perfect zucchini, either. 

For the aioli:

2 egg yolks

1 1/2 cup canola or grapeseed oil

1/2 cup olive oil

2 cloves garlic

3 tablespoons champagne vinegar

1 teaspoon salt (or to taste)

water

Shave the garlic on a rasp grater, if available. If not, chop as fine as possible, add 1/3 teaspoon salt, and keep chopping until it becomes nearly puree. Put aside.

Put the egg yolks in a mixing bowl and whisk. Add 1/4 teaspoon salt to help the yolks emulsify, and whisk some more.

Here’s where things get intense. You need to slowly add the canola oil into the yolk mixture. If you add it too quickly, the aioli will break, and frustration will ensue. I always err on the side of caution and go drop by drop for the first half cup of oil, then by the tiny drizzle for the second half cup, then by the small pour for the last cup. It might be slower, but I like to add the oil, then pick up the bowl with one hand and mix with the other. Put the bowl down and repeat. Take your time. Enjoy the workout.  

If the mixture gets too thick, add a splash of water to thin it out and make it easier for mixing. 

If your aioli does break, put it aside and start a new batch. Whisk a fresh yolk, then slowly add the broken aioli to the yolk as if it were plain oil. (I once heard that the key ratio is that you should never add more than 25 percent of the total mass in the bowl. If there is a cup of aioli in the bowl, you never want to add more than a quarter cup of oil.) 

When you have mixed in all of the canola oil, start with the olive oil. Olive oil is less stable than canola and more likely to break, so add it when the aioli has pretty much come together.

The aioli is ready when it reaches your desired thickness, which for my taste is at about the ratio of two cups of oil to two yolks. Add the garlic, vinegar, and more salt and water to taste. 

For the zucchini sandwich:

5 pounds Costata Romanesco zucchini (about 6” long)

1 head escarole

1 tablespoon olive oil

4 eggs 

homemade aioli (recipe above)

4 squishy burger buns

salt to taste

Cut the zucchini into rounds, about an inch thick. Salt them heavily — probably more heavily than you think necessary — and leave in a colander over the sink for an hour or so. This is really important. The zucchini will absorb the salt and season itself while losing moisture and concentrating flavor.

Rinse the escarole, then cut into half-inch ribbons. Heat a medium skillet over medium heat with a tablespoon of olive oil. (Pro tip: use the same nonstick skillet that you’ll use later for the eggs.) Add the escarole and a pinch of salt to season, then toss quickly in the oil. Add a splash of water to quickly steam the escarole. It’s ready when lightly wilted. Set aside.

When the zucchini is ready to go, heat a cast-iron pan over medium-high heat and add a generous amount of oil to thoroughly cover the bottom of the pan by about a quarter inch. Remember, this is a light sandwich, but also decadent, because it’s summer and you should enjoy yourself. 

While the oil is warming up, set up a nonstick skillet for the eggs. Heat to medium, then add a tablespoon or two of oil.

Drop the zucchini into the cast-iron pan oil and wait for it to thoroughly brown before flipping it over, about 3 minutes. While the zucchini browns, cook the eggs for about two minutes on one side before flipping and cooking for another minute. I prefer my eggs over-medium for these sandwiches.

When the zucchini and eggs are done, it’s time for assembly. Dollop some aioli onto the bottom bun, then the zucchini steaks. Top with wilted escarole, the egg, and the top of the bun.

Go sit outside in the sun and enjoy this un-BLT with a glass of rosé. 

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