Substitutes:

• Irish Whiskey: You can use bourbon or Scotch if you don't have Irish whiskey. I've tried both, and while they change the drink's character, they still make for a delicious Irish Coffee.
• Brown Sugar: White sugar or a sugar substitute like Stevia works without brown sugar. The flavor profile changes, but it's still tasty.
• Heavy Cream: Half-and-half or whole milk can work in a pinch. They won't offer the same luxurious texture, but they get the job done.

Making a Pitcher:

• Scale: To make a pitcher that serves 8, multiply all the ingredients by 8. That would be 12 oz of Irish whiskey, 8 teaspoons of brown sugar, 48 oz of hot coffee, and 8 oz of heavy cream.
• Mix: In a large pitcher, combine the Irish whiskey, brown sugar, and hot coffee. Stir well to dissolve the sugar.
• Serve: Pour the mixture into individual pre-warmed Irish coffee mugs, float the whipped cream on top, and serve immediately.

Making it Non-Alcoholic:

• Irish Whiskey Substitute: Use a non-alcoholic whiskey substitute or even a splash of apple juice for a fruity twist.
• Proceed As Usual: Use these non-alcoholic substitutes instead of the regular ingredients, follow the original steps, and enjoy a non-alcoholic version.

Making it Vegan:

• Heavy Cream Substitute: Use a vegan alternative like coconut or oat cream. Whip it lightly, just as you would with dairy cream.
• Brown Sugar: Ensure your brown sugar is vegan. Some brands use bone char in the refining process. Look for brands that specify they are vegan-friendly.