In a clean mixing bowl for an electric mixer with a whisk attachment, add egg whites.
In a large pot add water, honey and maple syrup, in that order, being careful not to get any of the mixture on the sides of the pot. Turn the heat to medium and let the sugar mixture cook undisturbed.
When the sugar syrup reaches about 225°F, start whipping the egg whites on medium-high speed. Once they have started to get frothy add the cream of tartar and salt. Whip to soft peaks.
When the the sugar syrup has reached 240°F, remove from the heat, turn mixer to medium and very slowly and carefully pour the sugar syrup into the egg whites in a thin, steady stream. Aim to get the syrup in between the bowl and the whisk attachment so you don’t spray the hot mixture everywhere.
Once all of the syrup is in, increase the speed and continue to whip for 8 minutes, or until the mixture is thick and glossy.
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The bowl and whisk attachment must be cleaned well because if there is any grease in it, it will prevent the egg whites from whipping up properly.
You can use a candy thermometer attached to the pot to monitor the temperature, or an instant read thermometer.
Use a large pot to prevent the sugar mixture from boiling over. If it is still boiling close to the edge of the pot lower the heat. It will take longer to come up to the correct temperature, but it will eventually.
Troubleshooting: If you mixture hasn’t thickened up and become glossy, either the sugar syrup was not the proper temperature, or you haven’t whipped the egg whites long enough. So If it isn’t looking properly try whipping longer to see if that helps.