1 1/2 oz of coffee liqueur
1 oz of Vodka
1 oz of amaretto almond liqueur (or almond liqueur)
1 splash of Coca-Cola (or coke)
1 oz of Kahlua coffee liqueur (or coffee liqueur)
For this to look like the polyjuice potion in the Harry Potter book, you have to layer the whole concoction. First the kahlua to give the base, then the vodka (which ever you prefer), then so forth. To simulate that the potion is bubbling, add the splash of coke at the top.