Cayenne. How much and what form?

Unlike Nancy I've had little success dusting an even layer of cayenne pepper over a dish at the end. I always get concentrated clumps of cayenne so some areas are tongue scorchers and other areas are super mild.

That's not a problem when you can stir the cayenne into a soup or stew but for preparations like this, it's easier to mix cayenne with a wet ingredient (like oil and in this case tomato paste) to evenly distribute the heat.

I'd use 1/2 teaspoon of cayenne since the recipe allegedly serves four. For matters of spiciness, it comes down to the individual cook's call since they know who will be sitting at their dinner table and what those guests' tolerances for spiciness might be.

Best of luck.

If I were making this (which sounds both easy and good), I'd leave out the cayenne from the foil pack - there are already many flavors in that pack, and the cayenne (absent or present) wont much change the over
Then, when you're plating and taking it to the table, add a spice jar of cayenne to the possible toppings and let people add as much or as little as they want.