Sweet mango lends brightness to this hearty side dish, a toss of Israeli couscous, nutrient-rich zucchini, and peppery fresh parsley. When buying zucchini, look for blemish-free, vibrant skins. Choose smaller squash, as they are younger and therefore more tender than their larger counterparts.
In a dry, medium saucepan over medium-low heat, toast couscous, stirring frequently, until golden-brown, 8 to 10 minutes. (You could skip this step in a pinch, but it's worth it!)
Peel mango; stand on its end with a skinny edge facing you and, with a knife close to the seed core, cut a 1-inch slice off each of the two sides. Then, cut each of those slices into two half-inch-thick slices. Slice zucchini lengthwise into 1/3- to 1/2-inch slices. Brush mango and zucchini pieces with vegetable oil on all sides, season lightly with a pinch of salt, and grill until charred and tender, 5 to 8 minutes. Let cool; cut into 1/2-inch chunks.
In a medium saucepan, bring chicken stock to a boil. Add couscous, stir, cover, reduce heat to simmer, and cook about 7 minutes. Add mango, zucchini, butter, parsley, and salt. Cook another minute and taste for seasoning and doneness. Keep warm. Makes 4 (1-1/3-cup) servings.