Pre-heat oven to 350 degrees.
Line baking sheets with parchment.
Have cookie cutter(s) ready.
In medium bowl add the flour, salt and baking powder, stir to combine, set aside.
In bowl of mixer start whipping the butter until light and fluffy.
Add the sugar and mix to combine.
Add in the egg, vanilla and vanilla bean. Mix well to combine.
Slowly add in the flour mixture and mix until cookie dough forms and all is combined.
Divide dough into two portions.
Place dough between two sheets of wax paper and roll out, cut out cookies and place on tray.
Bake for 8-12 minutes.
Repeat until all cookies are baked.
Let cool completely.
Combine all ingredients into mixer and mix until all combine and royal icing forms, about 5 minutes.
Pour into piping bag with a small round tip, I used Wilton tip #3.
Lay cookies flat on cookie sheets.
Outline the snowflakes with royal icing.
Let set for at least 10 minutes. This outline will be like a fence and will keep the royal icing from running over the sides when its time to fill.
Next fill each cookie with royal icing, using the tip or a toothpick to move it around so it covers evenly.
Sprinkle immediately with sprinkles while icing is wet.
Let set to dry completely, at least 4 hours but over night is preferable.