You need:
Puff pastry (Enough to fill the form you'll use for the pie)
4 Eggs
200 g Grated Emmentaler cheese
1/4 l Cream-Fraise
2 Cans of tuna in water (small cans)
2 Big onions
Some olive oil

So what do I do?
Make the base of puff pastry in your form and punch 1000 holes in it with a fork. 
This will stop the pastry from expanding when in the oven. Put the form in the 
fridge for now. Chop the onions and put them on a hot pan with a bit of 
olive oil until they're "clear". (But not brown).
Whisk the eggs with the cream-fraise in a bowl. Drain the water from the tuna and 
spoon the chunks into the egg/cream-fraise mixture along with onions and cheese. 
Now poor the mixture into the form with puff pastry and place in a 225 c hot oven 
for about 30 minutes.

This is my mother's recipe, so if you don't like the pie you'll have to take it up 
with her ;-) - personally I know few things better than this stuff...