Yellow rock sugar is also known as Chinese rock sugar. Unlike western granulated sugar, rock sugar is sold in solid, honey-coloured chunks. To use the sugar in recipes, you must break it apart. Using rock sugar will require the use of force and a heavy tool. "The Chinese Kitchen" recommends using a hammer rather than a rolling pin for breaking apart lumps of yellow rock sugar. Authors Deh-Ta Hsiung and Ken Hom note the hardness of the rock sugar could damage the wood of common kitchen rolling pins.
Place a lump of yellow rock sugar into a towel.
Fold the edges of the towel over the sugar to prevent broken chunks from falling out and to protect the counter.
Tap the sugar with a hammer through the towel until the lump breaks down into smaller pieces.
Add the broken down chunks of rock sugar to hot dishes or drinks so the heat further melts the sugar. Each lump of yellow rock sugar replaces 1 tbsp of white or brown sugar in recipes.
Break more sugar than you need and store the extra in an airtight container at room temperature indefinitely.