What are the 4 ingredients needed to make Irish coffee?

While Irish coffee is delicious and a classic, it actually only has three main ingredients:

1. Irish whiskey: This is the base spirit that gives the drink its signature kick.

2. Hot coffee: This provides the caffeine and warmth.

3. Brown sugar: This balances the bitterness of the coffee and whiskey.

The fourth ingredient is whipped cream, but it is optional and not necessary for the drink to be considered an Irish coffee.