Whisk the ricotta and egg yolks together in a large bowl to blend, then whisk in the buttermilk.
Sift the flour, baking powder, and salt into the ricotta mixture.
Stir with the whisk just until combined. Stir in 1 ½ cups of the cereal.
Using an electric mixer, beat the egg whites and sugar in another large bowl until firm but moist peaks form.
Using a large silicone spatula, gently fold the egg whites through the batter in 2 additions.
Heat a griddle or large nonstick sauté pan over medium-low heat.
Melt some butter on the hot griddle.
Working in batches, ladle about ½ cup of the batter onto the griddle for each pancake. Using the back of the ladle, spread the batter to thin out the pancake to about ½ inch.
Cook the pancakes about 3 minutes per side, or until they puff, become golden brown, and are just cooked through.