How to Make Sugar Skulls
If you want to make traditional sugar skulls, mix sugar, meringue powder, and water in a large bowl. Pack the mixture into the front and back molds, then scoop out some of the sugar and leave the molds to dry overnight with the sugar-side up. After they've set, flip out the skulls and attach the two halves with royal icing, then decorate them with different colors of icing. It's best to make these on a day with low humidity, as they may not set up properly on a rainy day.
Purchase your sugar skull mold. Buy skull molds with a front and back section from mexicansugarskull.com or a similar online store. Buy skull molds with a front-side only from Amazon.com. You can buy molds in small, medium and large sizes. Buy a large container of white granulated sugar.  Order merengue powder. This is a traditional baking ingredient used to hold together sugary frosting. CK Products, Wilton and Ateco make high quality meringue powder. This product costs about $7 for 4 oz. For large batches of sugar skulls, you will want to buy several containers. Wait for a low-humidity day. Most traditional Day of the Dead recipes say that the skulls will not form properly on a rainy day. Measure your ingredients and place them in a large bowl. Use 4 cups (800g) of sugar, 4 tsp. (13.3g) of meringue powder and 10 tsp. (49ml) of water.  You may add 2 extra tsp. (10ml) of water later. If you are making a large batch of sugar skulls, use 10 lbs. (4.5kg) of sugar, 1/2 cup (80g) of meringue powder and 7 tbsp. (104ml) of water. If you want to make colored sugar skulls, mix food color with the water before pouring it into the bowl. Mix together your skull recipe with your hands. Make sure you continuously incorporate the water at the bottom of the bowl with the sugar at the top, since the water will settle to the bottom. Add 2 tsp. (10ml) of water if the sugar isn't sticking together. Test the sugar. If you press the sugar together with your hands and your fingerprints imprint and stay, it is ready to mold. If the sugar falls apart or fails to imprint, there isn't enough water in your mixture. Pack sugar into the front and back molds with your hands. Pack it very tightly. Smooth the back of the mold with a straight edge. Scoop out the center of the skull with a spoon. Leave ⁄ 2 inch (1.3 cm) of sugar on all sides. Do not scoop out the neck portion, or it will be too fragile. You must remove this section to ensure the skull will dry quickly and evenly. Set the molds with sugar side up to dry overnight. They should take approximately 8 hours to dry. Flip out the skulls onto a piece of cardboard.  Make your royal icing. Pour 1/2 cup (40g) meringue powder with 1 cup (237ml) of water. Mix well with a hand mixer. Add a 2 lb. (0.5kg) bag of powdered sugar to the mixture. Put a layer of white royal icing on the back of each side of the skull mold. Stick the back and front of the skull together to dry. Allow them to dry for 4 to 8 hours before decorating. Separate royal icing into bowls. Pour in drops of food coloring and mix well. Decorate your skulls with colored royal icing. Buy your sugar skull molds. You can buy both front and back molds or simply the front, for a faster craft project. Pour 6 cups of granulated sugar into a bowl.  Separate 2 eggs from their egg whites. Put the egg whites into the bowl. Mix the recipe together with your hands. Test the sugar mixture with your hands. If you can press it in you hands and the fingerprints remain, it is ready. If it does not hold together, try mixing it better first, then add extra egg whites 1/4 at a time. Press the sugar into the skull mold. Make sure it is pressed very firmly or it will crumble later on. Use a straight edge to smooth the back of the skull mold. Remove excess sugar. Scoop out a rounded section with a spoon. Removing a circle in the middle of the skull will make it lighter and dry faster. Flip your skulls gently onto a piece of cardboard. Repeat with remaining skulls. Preheat your oven to 200 degrees Fahrenheit (93 degrees Celsius).  Place your cardboard on the rack inside the oven for 30 minutes. Allow them approximately 1 week to cure before the Day of the Dead. Make your royal icing. Combine 2 large egg whites with 3 cups (330g) of powdered sugar using a hand mixer.  Separate and color your royal icing with food coloring. Decorate them according to your preference. Purchase a silicon skull ice cube tray. They are available at dollar stores, Halloween stores and online. Mix together 1 cup (200g) of granulated sugar and 2 tsp. (10ml) of water in a bowl. You can use clean hands to ensure it is well mixed. Press the sugar into the ice cube tray. Press as firmly as possible. Try to make the back of the ice cube section as even as possible. Cover the back of the tray with a cookie sheet. Gently flip it over. Press lightly on the top of the silicone tray sections to loosen the skulls. Preheat your oven to 200 degrees Fahrenheit (93 degrees Celsius).  Put the cookie sheet inside the oven for 10 minutes.  Buy colored icing and decorate the sugar skulls. Serve them to guests at Halloween or Day of the Dead parties. 
Purchase your sugar skull mold. Buy a large container of white granulated sugar. Order merengue powder. Wait for a low-humidity day. Measure your ingredients and place them in a large bowl. Mix together your skull recipe with your hands. Test the sugar. Pack sugar into the front and back molds with your hands. Scoop out the center of the skull with a spoon. Set the molds with sugar side up to dry overnight. Flip out the skulls onto a piece of cardboard. Make your royal icing. Put a layer of white royal icing on the back of each side of the skull mold. Separate royal icing into bowls. Buy your sugar skull molds. Pour 6 cups of granulated sugar into a bowl. Separate 2 eggs from their egg whites. Mix the recipe together with your hands. Press the sugar into the skull mold. Scoop out a rounded section with a spoon. Flip your skulls gently onto a piece of cardboard. Preheat your oven to 200 degrees Fahrenheit (93 degrees Celsius). Place your cardboard on the rack inside the oven for 30 minutes. Make your royal icing. Purchase a silicon skull ice cube tray. Mix together 1 cup (200g) of granulated sugar and 2 tsp. Press the sugar into the ice cube tray. Cover the back of the tray with a cookie sheet. Preheat your oven to 200 degrees Fahrenheit (93 degrees Celsius). Put the cookie sheet inside the oven for 10 minutes. Buy colored icing and decorate the sugar skulls. 