If using fresh kale, trim off the tough stem and centre rib from each kale leaf. Coarsely chop the leaves, and then cook in boiling water 3 minutes. Drain kale well, cool in ice-cold water, and then drain well again, squeezing out as much water you can.
If using frozen kale, which is already chopped and par-cooked, simply thaw it and drain well, squeezing out as much water you can.
Place the cream cheese in a bowl and beat until light. Beat in the mayonnaise. Add the kale, garlic, juice, pepper sauce, onion and cheddar, reserving 1/4 cup of the latter.
Spoon the dip into a shallow, 4-cup baking dish. (Dip can be made to this point hours in advance. Refrigerate until needed).
Sprinkle top of dip with Parmesan and remaining grated cheddar. Bake in 350°F for 25 minutes, or until the dip is hot and light golden.