Preheat grill to medium heat
Pull outer husks on ears of corn down to the base of the corn and remove the silks the best you can
Fold husks back over corn and submerge in a large bowl of water for 8-10 minutes
Remove corn from water and shake off excess water. Place corn directly on grill and grill for about 15-20 minutes, turning the corn every 5 minutes or so
During the last 5 minutes of grilling, add halved or quartered red onion and lime halves to the grill
While corn is grilling, add mayonnaise, sour cream, cotija cheese, garlic, spices, jalapenos and cilantro into a blender and blend until smooth
Remove corn from grill and peel back husks
Add a little butter to the corn, then spoon cilantro lime sauce on top
Garnish with diced grilled onion, fresh cilantro, extra cotija cheese and a squeeze of lime juice
Enjoy!