Fregola With Charred Onions And Dill

Name: Fregola With Charred Onions And Dill
Ingredients: 1 cup fregola or Israeli couscous; 1 teaspoon kosher salt, divided, plus more for pasta water; 1 bunch spring onions, trimmed and halved lengthwise; 1 tablespoon olive oil; ½ teaspoon black pepper, divided; ½ cup (1 stick) unsalted butter, softened; 1 small shallot, finely chopped; 1 clove garlic, finely chopped; 2 teaspoons lemon zest plus 1 teaspoon fresh juice (from about 1 large lemon); ¼ cup chopped fresh dill, plus more for garnish