Đông lạnh khoai tây nghiền được nặn thành miếng dẹt đặt trong khay nướng bánh. Bảo quản món khoai tây nhồi và khoai tây hầm trong đĩa khi đông lạnh.

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in English about that?
Use your hands to mold your leftover mashed potatoes into .5 in (1.3 cm) thick patties. Place the patties on a baking sheet, then cover it with plastic cling wrap. Put the mashed potatoes into the freezer for about 24 hours. Then, combine the mashed potato patties into a single airtight container. It’s best to eat them within a few weeks, as mashed potatoes don’t freeze well. Cool the dish evenly by putting it in your refrigerator for about 1-2 hours. Cover the food with moisture-resistant parch