Bring a large pot of salted water to a boil and cook the rotini pasta according to package instructions until al dente; drain and rinse under cold water to cool.

While the pasta cooks, preheat a grill or grill pan over medium-high heat.

Brush the corn with a little oil and grill it, turning occasionally, until it’s charred in spots and cooked through, about 8-10 minutes.

Once cooled, cut the kernels off the cobs and transfer them to a large mixing bowl.

In a separate bowl, whisk together mayonnaise, sour cream, lime juice, chili powder, garlic powder, salt, and pepper until smooth and creamy.

Add the cooked pasta, diced red bell pepper, and chopped cilantro to the bowl with the grilled corn.

Pour the dressing over the pasta mixture and toss gently until all ingredients are well coated.

Fold in the crumbled cotija cheese, reserving some for garnish.

Transfer the pasta salad to a serving bowl, garnish with the remaining cotija cheese, extra cilantro leaves, and lime wedges on the side.

Refrigerate for at least 30 minutes before serving to allow flavors to meld.