royal icing recipe

ingredients

• 1/2 cup wâter
• 4 tâblespoons meringue powder
• 7 to 8 cups confectioner's sugâr 
• 1 teâspoon vânillâ extrâct
• 2 tâblespoons Crisco vegetâble shortening
• 2 tâblespoons light corn syrup

instructions

1. In â lârge bowl with ân electric hând mixer or in the bowl of â stânding mixer fitted with â wire whip, plâce the wâter ând meringue powder. Whip the mixture, stârting on low ând building up to high, until it's very fluffy ând peâks form. This mâke tâke â minute or two.
2. Grâduâlly âdd âbout hâlf the confectioner's sugâr ând mix well. âdd the vânillâ, shortening, ând light corn syrup ând blend.
3. âdd the remâining sugâr cup by cup, mixing well âfter eâch âddition, until the consistency you like is âchieved. 
4. I like to mâke my royâl icing on the thick side (so if you overturn â spoonful, it clings to the spoon ând only slowly fâlls bâck into the bowl) becâuse it's much eâsier to thin icing lâter with wâter thân it is to thicken with confectioner's sugâr. 
5. Store in â seâled contâiner ât room temperâture for up to â month. âfter decorâting cookies, let the cookies dry very well, overnight ât leâst, before pâckâging. 

Source: https://thedecoratedcookie.com/royal-icing-recipe/