Combine the heavy cream and white chocolate chips in a microwave-safe heatproof bowl. The cream will pool around the chips before heating brings them together.

Heat for 20 seconds at a time, stirring thoroughly after every burst, and stop when the mixture becomes smooth. The finished mixture should look glossy, with no firm chips remaining.

Stir the zest and yellow food coloring into the melted mixture, incorporating the lemon juice gradually as you stir. The ganache should have an even color and a smooth satin sheen.

Refrigerate the ganache for two hours to firm it for shaping. It should feel cool and hold a rounded spoonful instead of flowing back into the bowl.

Pass the powdered sugar through a sifter into a separate bowl. The sugar should look fine and fluffy, without compact lumps.

Scoop portions of chilled ganache with a spoon and briefly roll each between your palms to form balls. The centers should feel firm but pliable, with only slight tackiness.

Turn each shaped center in the sifted powdered sugar until coated. A light, even white layer should cover the surface.

Arrange the coated truffles on a parchment-lined cutting board or sheet pan and refrigerate for a final 30 minutes before serving. The finished truffles should hold their shape when lifted.