apples are a good stimulant to the brain 
Hey, i’m not sure how good it would taste… but you might consider orange juice as a possible ingredient? i honestly believe that OJ has helped me get lucid in the past. it seems like every time i drink it, i either have a LD, or i have a crazy vivid/long ND. just a thought…
ice cream, makes it more of a milk shake.
Try adding chocolate ice cream. Ice cream is a milk product, therefore it will help increase dream recall, and chocolate has a good effect on the content of dreams.
Try adding some cinnamon, nutmeg, and a very a small amount of garlic.
DO NOT read what is below, or you will be cursed, and never ever have LD’s again 
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I just made this up 
but i think if your subconscious thinks it will work it will work.