1. Bring a large pot of heavily salted water to a boil. Cook rotini 1 minute shy of al dente per package directions. Drain, toss immediately with olive oil, spread on a sheet pan, and refrigerate until fully cooled.

2. Whisk together sour cream, mayonnaise, lime zest, lime juice, garlic powder, chili powder, cayenne (if using), salt, and pepper in a small bowl until smooth. Taste and adjust seasoning.

3. Pat the thawed or drained corn dry with paper towels. For extra smoky flavor, toss corn in a dry skillet over high heat for 2–3 minutes until lightly charred. Let cool.

4. Add cooled pasta, corn, most of the Cotija, and cilantro to a large bowl. Pour three-quarters of the dressing over the top and toss well to coat every piece. Add more dressing to taste.

5. Transfer to a serving bowl or platter. Top with remaining Cotija, a dusting of chili powder, and extra cilantro. Serve immediately or cover and refrigerate up to 4 hours before serving.