At the moment you can create mixed drinks by making a recipe which requires drinks from this plugin.

For example:

grvdkbeer:
name: grassy vodka-beer
ingredients:
- Brewery:beer/1
- Brewery:vodka/1
- grass/2
cookingtime: 2
distillruns: 0
difficulty: 6
age: 0
alcohol: 13
color: GREEN

I've been working on a fork with mixed drinks since I made this issue. It's somewhat bittersweet finding out that it already exists.