In a bowl combine your mayo, sourcream, onion powder, garlic powder, salt and lime juice; set aside.
Place your 4 ears of corn (still in the husk) directly on the oven rack. I like to put a sheet pan underneath to catch any small pieces that fall off.
Roast the corn for 40 minutes.
When your corn is done roasting, peel down the husk and tie with a string to hold back the husk. ( I like using the husk for presenation, and as an easy way to hold and eat your corn.)
Drizzle your mayonnaise mixture all over the corn.
Garnish with chili powder, paprika, cotija cheese, and cilantro.