To get this trophy, you need to go on Mania Mode.
The easiest way is to select Green Hill Zone, at the end of Act 1. After finishing the boss, the goalpost will fall from the sky and you have to jump around and direct it towards the sunflower and between the two purple flowers on the map. If you do this correctly, both item boxes should pop from the ground. Get them and the trophy will pop.
This locations never change and you can get the item boxes at the end of every boss on Act 1 of any zone.
Here is a video to illustrate all that better (made by Jerry Appleby):