Preheat oven to 250. Beat eggs, cream of tartar and salt at high speed in mixer until foamy.
Gradually add the sugar and beat until stiff peaks form.
Add food coloring if desired.
Drop spoonfulls of batter on 2 cookie sheets lined with parchment paper. Bake for 45 minutes, then rotate the position of the cookie sheets in the oven and bake for 30 more minutes until cookies are very dry. Turn of oven off and let the cookies cool inside the oven