Preheat oven to 375°F. Butter the sides and bottom of a 4 cup soufflé or casserole dish.

Warm buttermilk in a saucepan over medium heat. Stir in cornmeal. Cook, stirring often, until mixture is thick and smooth, about 3 minutes. Stir in butter and salt and remove from heat. Let cool.

Whisk egg yolks into cornmeal mixture. Add green onions; stir we'll.

Beat egg whites until soft peaks form. Add to cornmeal mixture, a little at a time, folding gently to avoid deflating.

Scrape mixture into prepared pan. Bake 25 to 30 minutes, until puffed, golden brown and set. Serve immediately by spooning portions onto individual plates.