Hi there, can anyone tell me how to make these white flower petals? I'm not sure if they have been buttercream piped on, or cut out individually using fondant, modelling chocolate? Any suggestions would be greatly appreciated

These look like they were piped right on the cupcake with buttercream

use a 79 or 402 piping tip -- they come in other sizes too -- you might have to pinch the tip of the icing after you pipe it -- because you want your icing stiff so it stands up well but you also want it soft so it  makes a pretty point -- so I err on the side of real stiff icing and you typically start out on a nail with a rose type build up -- in this case a nice rounded cupcake top works --

best to you

I think they are marshmallow flowers.

http://www.werecallingshenanigans.com/2014/05/11/marshmallow-flower-cupcakes/

omg that's brilliant -- could definitely be