Kuku sabzi is a Persian omelet packed with enough herbs—such as cilantro, parsley, dill—and alliums that its color is deep green. This version is baked in the oven instead of cooked on the stovetop as is traditional, and it combines Swiss chard with dill and scallions. You will need 8 ounces of chard, or about half a standard-size bunch, to obtain the correct amount of stemmed and torn leaves. A food processor makes quick work of chopping the chard and herbs. We also include some baking powder to lighten the texture of the omelet and a little flour to bind the eggs. In order to incorporate these ingredients without clumping, we whisk them plus the seasonings with only two of the eggs before beating in the remaining six. The omelet is delicious with warmed flatbread, feta cheese and crisp radishes. Refrigerate leftovers, tightly wrapped, for up to three days.