3 tbsp meringue powder (not plain egg white powder)
9–10 tbsp room temperature water
Optional: gel food coloring
In a large bowl, mix butter and sugar until smooth. Beat in eggs and vanilla. Stir in the flour, collagen hydrolysate, baking powder, and salt.
Cover, and chill dough for at least one hour (or overnight).
Preheat oven to 400 degrees F. Roll out dough on floured surface 1/4 to 1/2 inch thick.
Cut into shapes with any cookie cutter.
Place cookies 1 inch apart on ungreased cookie sheets.
Bake 6 to 8 minutes in preheated oven. Cool completely.
In a large bowl using a hand mixer or a stand mixer fitted with a whisk attachment, beat all of the icing ingredients together on high speed for 1.5 – 2 minutes.
When lifting the whisk up off the icing, the icing should drizzle down and smooth out within 5-10 seconds. If it’s too thick, add a little more water. If it’s too thin, add a little more sifted confectioners’ sugar.
Icing completely dries in about 2 hours at room temperature.
If you’re layering royal icing onto cookies for specific designs and need it to set quickly, place cookies in the refrigerator to help speed it up.