1. Preheat oven to 200 degree F. Using a pencil and a 3-1/2-inch snowflake cookie cutter, outline snowflake shapes on 2 sheets of parchment paper large enough to line 2 cookie sheets, drawing 6 snowflakes per sheet. Turn paper over and place on cookie sheets.
2. Beat together egg whites, cream of tartar, and salt in a large bowl on low speed until frothy, about 30 seconds. Increase speed to high and beat until whites begin to thicken, 2 to 3 minutes. Gradually add super fine sugar and beat to stiff peaks, about 4 minutes.
3. Gently fold in food coloring.
4. Fill a pastry bag fitted with a 1/3-inch plain pastry tip with meringue. Tracing outlines, pipe snowflake shapes onto parchment paper. Sprinkle generously with decorating sugar.
5. Bake snowflakes in upper and lower thirds of oven, switching positions halfway through, until crisp, about 1-1/4 hours. Transfer snowflakes on cookie sheets to racks and cool completely. When cool, carefully peel paper off snowflakes. Makes 12 cookies.