The official IBA formulation for the Rusty Nail is nine parts of Scotch Whisky to 5 parts of Drambuie. This is a rather awkward formulation, so Instead I will suggest a simple 2:1 formulation:
2 oz Scotch Whisky
1 oz Drambuie
First fill an 8 oz tumbler glass with crushed ice.
Add the Scotch Whisky and the Drambuie
Stir gently until a the outside of the glass frosts.
Garnish with a lemon slice.
Note: If you are interested in more of my original cocktail recipes, please click this link (Cocktails and Recipes) for more of my mixed drink recipes!