|Olive oil||60 Milliliter (1/4 Cup)|
|Yellow onions||5 Small, thinly sliced|
|Smoked ham||1⁄4 Pound, chopped (115 Gram)|
|Grated parmesan cheese||60 Milliliter (1/4 Cup)|
|Minced fresh parsley||30 Milliliter (2 Tablespoon)|
|Dried marjoram||1⁄2 Teaspoon, crumbled (2 Milliliter)|
|Dried basil||1⁄4 Teaspoon, crumbled (1/4 Teaspoon)|
|Salt||1⁄4 Teaspoon (1 Milliliter)|
|Pepper||1 1⁄4 Pinch|
|Butter||30 Milliliter (2 Tablespoon)|
Heat oil in medium skillet over medium-high heat.
Add onions; cook, stirring frequently, until onions are golden brown, 6 to 8 minutes.
Drain chopped tomatoes and stir into onions; cook over medium heat, stirring constantly, 5 minutes.
Remove tomatoes and onions from skillet to large bowl with slotted spoon; discard drippings.
Let tomato-onion mixture cool to room temperature.
Add ham, cheese, parsley, marjoram, basil, salt and pepper to cooled tomato-onion mixture; mix lightly.
Whisk eggs in small bowl; stir into ham mixture.
Heat butter over medium heat in 10-inch (25 cm) heavy skillet with flameproof handle; when foam subsides, reduce heat to very low.
Add egg mixture to skillet; spread in even layer.
Cook without stirring over very low heat until all but top 1/4 inch (0.5 cm) of egg mixture is set, 8 to 10 minutes; shake pan gently to test.
Place skillet under broiler, about 4 inches (10 cm) from heat; cook just until top of egg mixture is set, 1 to 2 minutes.
Do not let top brown or frittata will be dry.
Frittata can be served hot, room temperature or cold.