In this task, you will be presented with the directions of a recipe separated by "," and have to fill in the "___" which is a step that is missing from the recipe.

Lightly brush one tablespoon olive oil on the cut sides of the rolls and lemon halves; set aside.,Combine remaining oil and vinegar in a small bowl.,Brush a little of mixture on zucchini and onion, then season with salt and pepper.,Grill zucchini and onion, over medium heat, until tender, about 2 to 3 minutes per side.,Meanwhile toast rolls, cut side down, about 3 minutes.,______
Place vegetables on rolls, top with feta and mint, if using; drizzle with remaining vinegar and oil and squeezed lemon juice.