01 - Bring a large pot of salted water to a boil. Add rotini or fusilli and cook according to package instructions until al dente. Drain and rinse thoroughly under cold water, then set aside.
02 - While the pasta cooks, heat a grill pan or skillet over medium-high heat. Add corn kernels and cook for 3 to 4 minutes, stirring occasionally, until lightly charred. If using pre-roasted corn, this step may be skipped.
03 - In a large mixing bowl, whisk together mayonnaise, sour cream, fresh lime juice, minced garlic, chili powder, smoked paprika, cumin, salt, and black pepper until smooth and well combined.
04 - Add cooked pasta, charred corn, diced red onion, red bell pepper, chopped cilantro, and green onions to the bowl with the dressing. Toss until all components are evenly coated.
05 - Gently fold in crumbled cotija or feta and chopped jalapeño if using. Taste and adjust lime juice, salt, or chili powder as desired.
06 - Transfer to a serving platter or bowl. Top with additional cheese, extra cilantro, and lime wedges. For best flavor, chill before serving.