Combine the gelatin and 1/2 cup of cold water in the bowl of an electric mixer fitted with the whisk attachment and allow to sit while you make the syrup.
Combine the sugar, corn syrup, salt and 1/2 cup water in a small saucepan and cook over medium heat until the sugar dissolves. Raise the heat to high and cook until the syrup reaches 240 degrees F on a candy thermometer. Remove from the heat.
With the mixer on low speed, slowly pour the sugar syrup into the dissolved gelatin. Turn the mixer to high and whip the mixture for about 15 minutes, until very thick. Add the vanilla and mix thoroughly.
With a sieve, generously dust an 8-by-12-inch nonmetal baking dish with confectioners' sugar. Sprinkle half the coconut evenly in the pan, pour the marshmallow mixture into the pan, smooth the top and sprinkle the remaining coconut on top. Allow to stand uncovered at room temperature overnight, until it dries out.
Turn the marshmallows onto a board and cut them in squares. Roll the sides in confectioners' sugar and store at room temperature.
To toast coconut, place it in a very large dry saute pan and cook over low heat for 15 to 20 minutes, tossing frequently, until lightly browned.
Photograph by Johnny Miller
Courtesy of Food Network Magazine