Preparation

• In a small saucepan, combine the milk, 1/4 cup of the sugar, and the cinnamon sticks. Set over medium-low heat and stir occasionally until almost boiling. Remove from the heat and let stand for 20 minutes. Discard the cinnamon sticks.
• Meanwhile, fill a medium saucepan with about 1 inch of water and heat until barely simmering. Wrap a damp towel around the base of a medium stainless-steel bowl to steady it. In the bowl, combine the egg yolks and the remaining 1/4 cup sugar. Whisk until thick and pale yellow, about 2 minutes. Whisking constantly, add the warm milk mixture to the yolks in a slow, steady stream. Set the bowl in the saucepan so it’s over but not touching the simmering water. Put the pot of water over medium heat and stir constantly with a wooden spoon until the mixture thickens slightly and an instant-read thermometer registers 175° to 180°F, 8 to 10 minutes. Check occasionally to be sure the water isn’t boiling hard, and don’t let the temperature of the sauce exceed 180°F or it may curdle.Strain the sauce through a medium sieve into a clean bowl and then set over an ice-water bath to cool, stirring occasionally. When cool, cover and refrigerate until ready to use.