Lemony Green Beans with Frizzled Leeks

2 1/2    pounds green beans, preferably haricot verts, trimmed

1           teaspoon kosher salt, plus more

3           lemons plus zest

2           large leeks, white and light-green parts only

1 1/2    cups duck or beef fat (available at health food stores)

1/2       teaspoon freshly ground black pepper

1.     Cook green beans in a large pot of boiling salted water until crisp-tender, 5–7 minutes. Drain, then immediately transfer to a large bowl filled with ice water. Drain again and pat dry.

2.     Meanwhile, zest lemons to yield 1 Tbsp. zest. Juice lemons to yield 1/4 cup juice, then slice any remaining lemons into wedges. Cut leeks crosswise into 4″ sections, then thinly slice lengthwise into matchsticks.

3.     Heat fat in a large deep-sided skillet over medium-high until shimmering. Cook half of leeks, stirring occasionally, until lightly golden brown and crispy, about 5 minutes. Using a slotted spoon, transfer to paper towels; season with salt. Repeat with remaining leeks; reserve oil in skillet.

4.     Cook green beans, pepper, lemon zest, and remaining 1 tsp. salt in reserved oil over medium heat, tossing occasionally, just until warmed through, about 5 minutes. Add lemon juice and toss to coat, then transfer to a platter. Drizzle about 1/2 cup oil from pan over; reserve remaining oil for another use. Top with leeks and serve with lemon wedges alongside.