While making this recipe for Zaar World Tour 8 (http://www.food.com/recipe/homemade-baileys-irish-cream-337038) I had to substitute the whiskey for scotch and my housemate, who loves scotch loved it. Therefore I'm saving my change here.
Pour the scotch into a blender and start adding ingredients, I added them in the following order; blending in between each addition (including a blend for each egg) Choclate essence, vanilla essence, cream, eggs, condensed milk.
Pour into a container (recipe makes approx 1 litre).
The recipe I adapted from suggests that you can store for up to 2 weeks, so I'm going to suggest you follow some very sound advice.