Scallions are quite frost-resistant and were still green and hardy when I pulled these last. I think they can actually be overwintered with some protection but that is an experiment for another year. When the ground is frozen, it is difficult to harvest them because the stems will break when you attempt to pull them from the ground, or else you get a huge clump of frozen soil and too many onions.
There are hundreds or thousands of uses for scallions, but the Chinese use them a lot both as a vegetable and as a seasoning. I have found that these Scallion Pancakes are easy to make and delicious all by themselves, but especially as a "bread" for Chinese-style meals. They are also good rolled up with meat mixtures like tacos. Try them for breakfast. They don't want any syrup or other sweet addition.
Scallion Pancakes
Beat 2 eggs and add milk to measure a total 2 cups.
Mix together 1 1/2 cups all-purpose flour and 1 teaspoon salt.
Add the egg/milk mixture to the dry ingredients, along with
1/3 cup peanut oil (or other neutral oil). Mix well.
Mix in 4 minced scallions.
Pour measured amounts of batter onto a greased griddle, one at a time.
(1/4 to 1/3 cup is about right)
Turn pancake after it is lightly browned on the first side.
May need to add scant oil between pancakes. Eat hot. May be frozen.