To make firm white royal icing at home, you will need to mix together powdered sugar, meringue powder, and water in a mixing bowl. Start by whisking the powdered sugar and meringue powder together, then gradually add in the water while mixing until the icing reaches the desired consistency. You can adjust the thickness of the icing by adding more powdered sugar for a firmer consistency. Once the icing is mixed, it can be used to decorate cookies, cakes, or other baked goods. **

Powdered sugar icing, also known as confectioners' sugar icing or glaze, is a simple and versatile icing made by combining powdered sugar with a liquid such as water, milk, or lemon juice. It is commonly used to drizzle over baked goods like cookies, cakes, and pastries to add a sweet and decorative finish. Powdered sugar icing can be flavored with extracts like vanilla or almond, and can be tinted with food coloring for a more decorative touch. **

The icing may not be hardening due to a few reasons. One possibility is that the ratio of ingredients in the icing recipe is off, such as too much liquid or not enough sugar. Another reason could be that the icing was not beaten for long enough to reach the desired consistency. Additionally, if the icing is exposed to high humidity or heat, it may have difficulty hardening properly. **

The cake icing is typically dry when it has hardened and no longer feels wet or sticky to the touch. This process can take anywhere from 1 to 4 hours, depending on the type of icing used and the thickness of the layer applied. To speed up the drying process, the cake can be placed in a cool, dry area with good air circulation. **

To dye icing black, start with a chocolate icing base to achieve a darker color. Then, gradually add black food coloring gel or paste to the icing, mixing well after each addition. It's important to add the coloring slowly to avoid making the icing too dark too quickly. Keep in mind that the icing may continue to darken over time, so it's best to let it sit for a while before adding more coloring. **

Chocolate icing does not harden because it contains a high amount of fat, typically from butter or cream. This fat content prevents the icing from setting and hardening like a glaze or royal icing. Additionally, the presence of cocoa powder or melted chocolate in the icing also contributes to its soft texture. The combination of fat and moisture in the icing keeps it soft and spreadable, making it perfect for frosting cakes and cupcakes. **

To make lemon icing, start by mixing powdered sugar and lemon juice in a bowl until smooth. You can adjust the consistency by adding more powdered sugar for a thicker icing or more lemon juice for a thinner icing. For a stronger lemon flavor, you can also add some lemon zest to the mixture. Once the icing is ready, you can drizzle it over your baked goods or spread it on top for a delicious lemony finish. **

To dry royal icing, you can simply leave the decorated item out at room temperature for several hours or overnight. You can also use a fan to speed up the drying process. Another method is to place the decorated item in a low-temperature oven with the door slightly ajar to allow moisture to escape. It's important to make sure the icing is completely dry before handling or storing the decorated item. **