Avocados are a great lunchtime snack, but once they're cut they start turning brown quickly. Cooking blog The Family Dinner suggests you preserve them with a slice of lemon to keep them green and fresh.
This is a familiar trick for stopping apples turning brown, but it works equally well with avocados. As the blog explains explains:
Cut the avocado in half and remove the pit. With a small knife cut a cross-hatch pattern through the avocado pulp down to the skin, being careful not to cut through the skin.
Cut one or two slices of citrus and lay them on the cut surface of the avocado. Sandwich the other avocado half on top and wrap tightly. At lunchtime just squeeze the avocado and the little cubes will pop right out, perfectly perkily green.
Definitely a good way to enhance your lunch.
Cooks Tip: Keeping an Avocado Green [The Family Dinner]