Add all ingredients into a shaker and lightly mix.
Add ice and stir to chill.
Strain and pour into rocks glass over fresh ice.
*Wagyu-beef-fat-washed Hibiki Japanese Harmony whisky: Melt 4 1/2 oz wagyu fat in a pan. Add 1 750 mL bottle of Hibiki Japanese Harmony whisky into a container and pour fat over. Seal and gently shake to mix over the course of 30 minutes. Chill in freezer overnight. Strain liquid through a coffee filter into a bottle. Filter twice to remove any unwanted fat.
**Salted caramel liqueur: Add 1 cup sugar and 1 large pinch of salt to a pan over a medium-high heat. Allow sugar to melt and caramelize. Add 2 cups vodka (or neutral spirit) and stir to mix. Return to a low heat and add 1 cup sugar while continuing to stir to dissolve any residual solids. Allow to cool and bottle.