Sauté the scallions in 3 tablespoons butter until they are soft. Set the
scallions aside and let cool.
Sift the flour, baking soda and salt into a large mixing bowl. Cut the 1/2
cup butter into small pieces and cut it into the dry ingredients until the mixture
resembles coarse crumbs.
In a small bowl mix together the 3/4 cup buttermilk and the green food coloring,
until it is a very dark shade of green. Make a well in the center of the flour
mixture, and add the scallions and the green buttermilk. Mix until a very sticky
dough just holds together. Turn out onto a floured surface and knead 20 times.
Pat out until 1/2 inch thick. Cut with a 2-inch cutter. Place biscuits on a
baking sheet about 3 inches apart.
Mix the melted butter and buttermilk and brush on the biscuits.