I'm making a wedding cake for this next weekend and I'm attempting to make this flower today, but I am lost on where to even begin.  Normally I'm pretty good at this stuff, but as to what kind of cutter, how to dry it, all that, is just stumping me!  Any and all advice would be very helpful! :)  

I would use five petal cutters in three different sizes (rose cutters would do nicely), and really go to work on the edges with a large ball tool.  As for drying, given the size I'd dry them in fruit trays so as to not cup them too much. I'd support the ruffled edges with bits of foam or small rolls of parchment paper while they dry.  Good luck and hth. 

I think that you can use a wilton rose cuter, I can see 2 big and one small petals, and use the ball tool on the edges , dry them over night resting on something to keep the shape that you desired  .. I´m really new on this but thats what I see 

Yeah...i agree with Doritta. Wilton rose cutter and dry on extra large flower cup or shape aluminum foil to fit your size needs.
 

You could also dry them in fruit nappies or deep saucers with bits of foam or rolled parchment paper to hold the ruffles.