The sweetness of bell peppers — they’re never hot, unlike nearly all of their relatives — is especially pronounced in summer, which is also when you’re most likely to wind up with one that was grown domestically. Even a green pepper — which is unripe — is sweeter when the weather is hot.
A good red pepper is the sweetest and most flavorful of the lot — yellow and orange are simply other varieties — but there’s no denying that a multicolored tangle of peppers is a beautiful thing, and that even the relative bitterness of green peppers adds complexity to the mix. In any case, you can use any color pepper you like in any of these recipes.
Unless noted, use a pound of peppers in all of them. That’s roughly equivalent to two whole large peppers, three cups sliced or 2 1/2 cups chopped. Core and seed everything. My favorite method is just to cut around the core, standing the pepper up and slicing it like an apple from the outside.
One of the most basic and wonderful preparations for bell peppers is roasting; a roasted red pepper with olive oil, capers or anchovies (or all three) remains one of the great, simple joys of this territory. Put whole peppers on a baking sheet lined with foil and roast in a 450-degree oven, or broil, turning the peppers as each side browns, until they have darkened, even blackened, and collapsed. (A hot grill is even better.) Gather the corners of the foil and wrap up the peppers; cool until you can handle them, about 15 minutes, then remove the blackened skin and seeds. (Do this under running water to make it easier; you probably won’t get all the skin off, and that’s O.K.)
The recipes are thorough, but far from exhaustive. Peppers combine beautifully with eggs, with vinegar and with eggplant and probably a dozen other ingredients I didn’t have the space to get to.