potato in quiche
I've done a "country french omelet" which would be similar and I do cook the potatoes first. I do a "rif" on Ina Garten's version and add more varied veggies (peppers & mushrooms). But having the potatoes cooked definitely is the way to go. Here is a reference: http://www.foodnetwork.com/recipes/in...
Hope that helps. Just do the same with the quiche.
In a Spanish potato omelet (tortilla espanol), the potatoes are cooked first (traditionally poached in oil). It is different from a quiche in that the proportion of 'filler' is higher, and the amount of non-egg liquid is lower. So its not the same, but I suspect potatoes need the same sort of preparation.
You definitnely want to cook the potato at least to the half-done stage, sylvan. It also pays to have them cooled and standing by instead of being freshly cooked and piping-hot. The main benefits to following these guidelines are: ensuring that it is fully cooked; letting the potato's own water leach into the boiling water (so it doesn't leach into the egg custard and mess up the proportions, or even worse, create nasty, watery pouches in the body of the pie.) And the reason for letting them cool is to avoid them changing the temperature of the custard directly surrounding them, which can result in a rubbery result. (The "cook ahead and let cool" rule also pertains to the other quiche ingredients.)
I know it might sound picky, but delicate things call for careful measures, right?
Enjoy. I'm sure it will be delicious.