1. Add the ingredients
Combine all the ingredient in an ice-filled mixing glass and stir well.
(If you don't have 1:1 simple syrup, you can make this by combining equal quantities of sugar and water in a pan and heating until the sugar dissolves)
Serve this cocktail in a tumbler, over one large cube or several small ones. You could even use an ice ball if you prefer.
Twist a piece of orange zest over the glass to release the aromatic oils.
Use orange peel and sprig of toasted rosemary to finish your Old Fashioned.