3 large ears of yellow corn, husked
2 small zucchini, halved lengthwise
1 tablespoon vegetable oil
1 lime
1 medium avocado, finely diced
1 small tomato, cored and finely diced
2 tablespoons finely diced red onion
½ cup sour cream
½ teaspoon cumin
½ small jalapeño (leave in the seeds for spicy!), finely minced, plus more for seasoning
2 tablespoons chopped cilantro, plus more for garnish
3 tablespoons crumbled Cotija cheese
½ teaspoon kosher salt, plus more to taste
Freshly ground black pepper to taste
Grill the vegetables
Preheat a grill or grill pan over high heat. Add the corn and grill, turning every 2–3 minutes, until blackened in spots on all sides, 10–12 minutes total. Transfer to a plate and let cool.
Brush the zucchini with the oil and season generously with salt and pepper. Grill, flipping once halfway through, until tender and lightly charred, about 10 minutes total. Remove to a plate, let cool for 10 minutes, then chop into small pieces.
To cut the corn off the cob, place a small bowl upside down inside a larger bowl (this helps catch the kernels). Stand each ear of corn on the smaller bowl and, using a sawing motion, cut the kernels from the cob, getting as close as possible without cutting into the woody core. You should have about 2 cups of corn.
Make the dip
Zest the lime into a medium bowl, then juice half of it into the bowl (about 1 tablespoon juice). Reserve the remaining half for seasoning at the end.
Add the avocado and toss to coat. Add the grilled corn, zucchini, tomatoes, and onions. Gently stir in the sour cream, cumin, jalapeño, ½ teaspoon salt, and cilantro. Season with additional lime juice and jalapeño to taste.
Transfer the dip to a serving bowl and garnish with Cotija cheese and more cilantro.
