No probs Paddy, the picture looks more like a quiche and thicker than an omelette, but i always finish mine under a hot grill, it makes it "rise up" and finishes it off nicely.
a frittata has at least 6 eggs in in along with potatoes cheese tomatoes ham salami onions (whatever) and stays in the pan you then put it in the oven to cook the top it looks like a big pie ...and then you slice and serve (4-6 people)... an omlette 2 eggs takes about 5 mins serves one