Gather ingredients: corn on the cob (or frozen corn), mayonnaise, Mexican crema or sour cream, cotija cheese, lime juice, chili powder (or Tajín), salt, black pepper
Cook the corn: boil 5–8 minutes until tender, or grill 10–15 minutes turning occasionally, or roast in the oven at 425°F/220°C for 20–25 minutes
Let corn cool slightly, then cut kernels off the cob (or keep cobs whole)
Mix sauce: stir together mayonnaise, crema (or sour cream), lime juice, and a pinch of salt and pepper
Coat the corn: brush or spoon sauce over the corn (or toss kernels with sauce)
Season: sprinkle chili powder (or Tajín), then add cotija cheese
Finish: add extra lime juice and a pinch more chili powder if desired
Serve immediately