Saute onions in olive oil until very gentle.
Add thinly sliced waxy potatoes, turn a few times, cover, and simmer until tender.
In a bowl, beat eggs with cheese, salt, pepper, and parsley.
Add cooled potatoes and onions to the egg mixture or pour the egg mixture over the potatoes and onions in the skillet.
Cook over medium-low heat until eggs solidify and form a brown crust underneath.
Flip the frittata to cook the top using one of the suggested methods.
Serve immediately or let cool for better flavor.
