On a charcoal or gas grill heated to 400° F or a very hot cast iron skillet, cook corn for about 3 minutes per side, without moving, until lightly charred. Rotate corn and continue cooking until all sides are deeply golden and then set aside.
While corn is cooking, stir together the crema, mayo, cilantro, garlic, chili powder, lime zest and juice, and salt to taste.
To serve, liberally coat grilled corn with crema mixture and top with chili powder, cilantro, cotija, and additional lime juice to taste.
Notes
Optional: Prefer your corn off the cob? Follow the directions above and simply cut your kernels off the cob and combine ingredients in a large bowl for a simple summer side dish.