From the Super Mario Wiki
The Special Shake is a food item that can be found in Paper Mario. It looks like a portion of green juice in a glass, with a pink bent straw in it.
Making this recipe requires a Melon from Lavalava Island and an Apple from Boo's Mansion, though the Apple is optional. Bringing these Items to Tayce T. will make the Toad chef cook both objects and turn them into a Special Shake. Special Shakes are recovery items and as such they are usable both inside and outside of battles. Using them replenishes twenty of Mario's Flower Points.
||Result of Cooked Item
|Apple + Melon