01 - Bring a large pot of salted water to a boil. Add pasta and cook according to package directions until al dente. Drain and rinse under cold water to cool completely. Set aside.
02 - Preheat a grill or grill pan over high heat. Grill shucked corn, rotating to lightly char on all sides, about 8–10 minutes. Allow to cool, then cut kernels off the cobs. For frozen corn, sauté in a dry skillet over medium-high heat until slightly charred.
03 - In a large mixing bowl, whisk together mayonnaise, sour cream, lime juice, chili powder, smoked paprika, cumin, salt, and black pepper until fully smooth.
04 - Add cooked pasta, charred corn kernels, diced red bell pepper, sliced green onions, chopped cilantro, crumbled Cotija cheese, and diced jalapeño, if using, to the bowl with dressing. Toss thoroughly to coat all ingredients.
05 - Taste and adjust seasoning as needed. Chill in the refrigerator for at least 30 minutes before serving to enhance flavors.