Ingredients

• 1 small red onion, very thinly sliced
• 1/2 cup red wine vinegar
• 1 tablespoon sugar
• Kosher salt
• 1/4 cup coarsely chopped oil-packed Calabrian chiles from a jar
• 4 large zucchini (about 2 pounds total), halved lengthwise, leaving stems on
• 3 tablespoons plus 1/4 cup olive oil
• 1/2 cup torn mint, plus more for serving

Instructions

1. Prepare a grill for medium heat. Combine onion and vinegar in a large bowl and let sit 10 minutes. Mix in sugar and a generous pinch of salt, then add chiles; set chile mixture aside.
2. Toss zucchini on a rimmed baking sheet with 3 Tbsp. oil; season with salt. Grill, turning halfway through, until steamy and tender within and charred all over, 12–16 minutes. Transfer back to baking sheet and let cool slightly.
3. Tear zucchini into 1 1/2"–2" pieces and add to reserved chile mixture. Add remaining 1/4 cup oil and toss to coat; season with salt. Add mint and toss gently just to distribute. Let sit 5 minutes to allow flavors to come together.
4. Transfer zucchini mixture to a platter with a slotted spoon; top with more mint.