3+ egg omelette in a pan
I'm quite new to making omelettes, but when I make a thick/Spanish omelette on the stove (gas) I do a few things that help.  I don't want to turn the grill on just to finish an omelette off, and the handle of my frying pan couldn't really take the grill anyway.


Push the edges in at first as if cooking a French omelette (to make a thicker, stronger layer quicker).  
Turn the heat down and put a lid on, but not for long.
Slide it out onto a plate bigger than your frying pan.
Invert the frying pan over the top of the plate. Wearing oven gloves hold them tightly together and flip.
Continue cooking.


I usually make these because I want them chock-full of onion, potato etc. -- otherwise I make French omelettes, which can be thicker than they traditionally should be (and in that case may be called English).  

Alternatively I often precook a filling (onion/peppers/garlic/herb/chillies) and reserve, adding it hot along with some cheese just before folding, while the top is still runny.  It finishes cooking through quite quickly at that point.  Turning is tricky as I tend to overstuff them (it's a favourite quick dinner at the moment,  with freshly-harvested new potatoes so I don't want to be mean with the filling).