Look no further for a speedy appetizer that everyone will want to gobble up. These two-bite open-facers are pleasingly retro. Although you can use thin toast like pumpernickel, rye, or whole wheat, we actually prefer good old sliced white bread. The toasts are spread with a mixture that tastes a little like creamy spinach dip (minus the spinach). Magic happens in the oven: the thinly sliced zucchini softens while the cheese bubbles and the bread crisps. The results get topped with a bit of sliced scallion right before serving for an extra touch of freshness.