P.P.
I use the Wilton class buttercream recipe, which comes out white.
1c shortening (get a nonhydronated brand like Spectrum)
4c powdered sugar
1Tb meringue powder
1/2tsp CLEAR vanilla. - that's important!
1/2tsp CLEAR butter flavor
2Tb water
Beat with a mixer until fluffy. Add additional water to thin out buttercream for spreading on a cake.