How do I scale serrano chile? I'm following a recipe that calls for 2 chiles serranos and serves 6. The dish is not hot/spicy at all, and I wouldn't want to lose this when scaling.

I need to scale by 6, and the dish should serve about 36 persons. Should I now use 12 chiles serranos?

They will be cooked with the rest of the ingredients, adding some flavour. Unless I'm missing something about this recipe, you are not supposed to eat the chiles!

This is the recipe I'm following. It's from a Diana Kennedy book.

I don't want the dish to become super hot!!!
I would follow the age-old cooking rule that says you can always add, but you can never take away. In other words, I'd add, say, 6 chillis, see how that tasted, and add more if you think it needs it.