2oz Old Tom Gin
1oz simple syrup
.5oz lemon juice
.5oz grapefruit juice
1/2 bottle Imperial IPA/DPA/Hoppy Modern IPA
Shake till really cold and put in a highball with a single large ice cube. Carefully poor beer on the cube to get a nice layered effect.
The sweet from the Old Tom and syrup tone down the bitter of the beer while the citrus plays off the hoppy citrus of the beer. Dangerous as it's a lot of booze per drink.