In a large bowl, whisk together the eggs, half of the Parmesan and all of the Cheddar with a generous pinch of salt and a regular pinch of pepper. Set aside.
In a frying pan that can go into the oven (no plastic parts!), heat the olive oil.
Saute the onion until softened.
Add the salami and garlic, and continue sauteeing until the reddish oil of the salami has mixed into the onion and garlic bits.
Throw in the kale, sprinkle in a bit of salt and pepper (how much depends on how salty and spicy your salami is) and cook, stirring occasionally, until the mixture is quite dry.
Pour in the egg and cheese mixture and stir well.
Allow the eggs to partially cook (edges firm but center still jiggly).
Sprinkle the remaining Parmesan on top and transfer to the preheated oven.
Let the frittata finish cooking in the oven until the top is lightly browned and crisp, about 15 minutes.