Need a Little Sunshine? This Weeknight Fish Has It in Spades.

When I saw a copy of Danielle Alvarez’s cookbook, “Always Add Lemon,” I knew I’d found a kindred spirit in the kitchen.

That title is also my mantra, and a squeeze of lemon, my secret weapon. It’s the finishing touch that brightens nearly everything I cook, whether it’s a sheet pan of roasted vegetables or a sizzling platter of sausages grilled until crisp.

I keep a little bowl of seeded wedges at the ready in the fridge. That way, when my braised lentils or pan of pasta needs a jolt, I can squirt in lemon juice without having to fish out the pits. My daughter, the family salad maker, uses them nightly for dressing. She squishes a wedge into the bottom of the salad bowl, adds a pinch of salt, a few grinds of pepper, then whisks in good olive oil. (Vinegar can seem harsh when you’re used to lemon’s gentle tang.)

Those handy wedges add zip where you’d least expect it. I squeeze them into BLTs, into chicken noodle soup, on the buttered, salted celery I nibble for a snack. And no seltzer glass in the house is complete without lemon floating among the ice cubes.

It’s an obsession Ms. Alvarez captures perfectly in the introduction to her book.

“A little bit of lemon will change everything,” she wrote. “My chefs joke that ‘Did you add lemon?’ should be inscribed on my tombstone. It is the question I consistently ask as plates leave the kitchen. Sometimes a few drops is all a dish needs to really sing.”

Even if you don’t necessarily subscribe to this lemon-in-everything philosophy, adding it to fish, especially fish drizzled with brown butter, is essential.

In Ms. Alvarez’s book, whole, bone-in John Dory is adorned with lemon slices, roasted, then covered in a caper-strewn brown butter. Naturally, more lemon juice spikes the sauce at the end.

Until this point, the dish is very classic. But she goes one step further and slicks the top of the fish with nori oil for an umami kick. This dish is bright and deep, with a silky texture that’s easy to achieve.

In my version, I substitute fillets for the whole fish. Then, instead of toasting nori sheets to make the oil, I swap in crumbled nori seaweed snack sheets. The whole thing is as good as the original, but easier to throw together on a weeknight.

All it needs is a (preferably lemony) salad to round out the meal.

Recipe: Lemony Fish With Brown Butter, Capers and Nori

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