These easy sandwich stackers feature layers of sliced avocado, sliced tomato, lettuce, sliced cucumbers, and Swiss cheese. They're perfect for a summer supper.A healthier version of the BLT, this sandwich is nutrient-rich. Avocados are fattening, but they provide heart-healthy monounsaturated fat. Avocados are also high in fiber. They can be used as healthy baking and cooking alternatives for butter and shortening.