Strip all the husks and silk off your corn. Rinse the ears under cold water to get any remaining silk off, then pat them dry with paper towels.
In a bowl, mix together the mayonnaise, Mexican crema (or sour cream), and minced garlic.
Fire up your griddle and let it preheat to medium-high heat, around 400-425°F. Give it a solid five minutes to come up to temp evenly across the whole surface.
Brush or rub each ear of corn with vegetable oil, coating all sides lightly.
Place your corn directly on the hot griddle. Let each side cook for about 2-3 minutes before rotating. Keep rotating the corn every few minutes until all sides have good color, about 10-12 minutes total for medium-sized ears.
Once your corn is nicely charred on all sides, pull it off the griddle. While it's still hot, use a brush or spoon to slather the mayo-crema mixture all over each ear.
Immediately after coating with the crema mixture, roll each ear in the crumbled cotija cheese. Then sprinkle with chili powder and smoked paprika. If you want extra heat, add a light dusting of cayenne.
Finish with chopped fresh cilantro and a squeeze of lime juice over each ear.