Heat a large skillet over medium heat and add melted butter until it begins to bubble.
Cook the garlic, stirring, for 1 minute until it becomes fragrant. Then, add the corn and continue to cook, stirring frequently, for 5 to 8 minutes until it has caramelized and has some charred spots.
Using a slotted spoon, move the cooked corn to a large bowl and set it aside.
Reserve a portion of red onion (2 tablespoons) and cilantro (2 tablespoons), and add the remaining red onion, cilantro, and jalapeños to the corn in the bowl.
In a medium bowl, combine mayonnaise, sour cream, chili powder, and salt.
Add the mayonnaise mixture to the corn, stir well, and then mix in cotija cheese and 2 tablespoons of lime juice. Adjust with more lime juice as desired. Cut the remaining limes into wedges.
Add the corn mixture to the cups, then top with the saved red onions and cilantro. Serve with lime wedges on the side.