Line a loaf pan with parchment paper. Set aside.
To make the icing:
- In a large bowl, beat the egg white with a handheld electric mixer until stiff peaks form.
- Add the granulated sugar, vodka, and lemon juice, and continue mixing. Add in the confectioner' sugar and food coloring, and mix until you reach the consistency of a thick icing. Set aside.
To make the sugar syrup:
- In a small heavy-bottomed saucepan, combine the granulated sugar and water. Bring the mixture to a boil over high heat and reduce the heat to medium-low until the sugar reaches a light caramel color.
- Reduce the heat to medium-low and add the egg white mixture to the pan, quickly mixing it in until well combined.
- Transfer the mixture to the prepared loaf pan and let rest at room temperature until hardned, about 3 hours or overnight.
- Turn it out of the pan and break into irregularly shaped pieces of coal.