Café Royal Cocktail Book by W. J. Tarling (1937, p.106)
| 0.1 part | lemon juice | acid |
| 0.4 part | gin — Seager's dry gin | base |
| 1 dash | peach bitters | bitter |
| 0.3 part | Lillet — Lillet | modifier |
| 0.2 part | van der hum — Van der Hum | modifier |
- Shake.
Happy Days is Seager's dry gin, Lillet, Van der Hum, lemon juice, and peach bitters.
Café Royal Cocktail Book by W. J. Tarling (1937, p.106)
| 0.1 part | lemon juice | acid |
| 0.4 part | gin — Seager's dry gin | base |
| 1 dash | peach bitters | bitter |
| 0.3 part | Lillet — Lillet | modifier |
| 0.2 part | van der hum — Van der Hum | modifier |
See also: Happy Daze