Line the rimmed cookie sheets with foil. 

Divide the buttercream frosting into 4 or 5 bowls and tint them whatever colors you are planning on using. 

Put one color in each piping bag or zip top bag and cut off the ends. Place the bags of frosting on one of the rimmed cookie sheets.

Place different colored sprinkles in cupcake liners.   Place the cupcake liners on one of the rimmed cookie sheets.

Place the cookies on the third rimmed cookie sheet. You won't be able to fit them all on the cookie sheet so have your child decorate 8 or 9 at a time then transfer them to a wire rack or plate to set overnight.

Allow your little one to put the frosting on the cookies then put the sprinkles on top. 

Allow the cookies to dry overnight then you can package them and give them as gifts or enjoy them!