You will need the Flower Power board unlocked first, which comes pretty quickly as you level up.
Load up the Superscore! Challenge on Pineapple Farm and select the mentioned Flower Power. All that's left is to gain 40k worth of points in order to 3 Star the track. The tricky part about this is the board, it has the lowest Awesome Meter rating so the meter depletes pretty quick. Try to keep the meter up by doing jumps and collecting coins, also you really want to use the grind rails for lots of extra points. Also try to ride tunnel walls for loopings which are worth a lot of points as well.