This drink gives you the instantaneous spark of tasting an old fashioned sweet potato pie.

Begin with a water glass like restaurants used in times past. You will have to look for these in antique shops.

Here is a picture of such a glass containing the last sips of the drink. It is a little less than 4 inches tall. 

Start with 3 to 5 ice cubes from the refrigerator ice maker. These are usually of a crescent shape, as in the picture.

Add a two ounce shot of the cheapest vodka, 80 proof.

Add a two ounce shot of a diet-caffeine-free generic Pepsi type cola. Pour it in fast enough to mix it. A little more than two ounces is OK.

Slowly pour a capful of white rum onto the ice, so that the rum floats on top.

Carefully raise the glass and take a big sip off the top, and swirl it around in your mouth. The rum and cola will give you a charge of sweet potato pie taste.