Very Old Fashioned

This isn't actually especially old - it's just the best name I could come up with on short notice.

1 1/2 oz Plantation 20th Anniversary Rum
1/2 oz Laird's Apple Brandy
1/4 oz mezcal (Vida)
1/4 oz pineapple syrup
3 dashes Bitter Truth Celery Bitters

Stir over a large ice cube in an old-fashioned glass.  FUCK GARNISH.  That's the kind of mood I'm in.  Booze in a glass, dammit, and fast!