For a delicious dessert, put a scoop of vanilla ice cream on a waffle and top with this sauce.

Combine in a medium heavy saucepan:

Stirring constantly, bring to a boil and cook until the last drop of sauce that falls from the spoon makes a short thread (230° to 234°F). Remove from the heat and add:

Stir briskly until the butter is melted and the sauce is thick and creamy. Whisk in a medium bowl until light and frothy:

Slowly whisk the hot maple syrup mixture into the egg. Rinse out the saucepan, making sure to dissolve any sugar crystals, then dry the saucepan thoroughly. Return the sauce to the saucepan and cook, stirring constantly, over medium heat until the sauce comes to a simmer and is thickened. If desired, stir in:

Serve at once, or let cool, cover, and refrigerate for up to 3 days. Reheat over low heat, stirring; if the sauce separates, remove it from the heat and whisk in a little hot water.