First, prepare the Apple Syrup: To a pot, add 2 Cups Diced Apples, 1 Cup Water, 3/4 Cup Maple Syrup, 1/4 Cup Brown Sugar, a Pinch of salt, 2 Cinnamon Sticks, 1/8th tsp Nutmeg, and 1/2 tsp Vanilla Extract. Simmer on low for 20-30 minutes. Remove cinnamon sticks. Allow the syrup to cool completely. Blend the cooled mixture until smooth, then strain it through a fine-mesh sieve. Store the apple syrup in an airtight container in the fridge.
Now, prepare the Maple Apple Sour cocktail: To a shaker, add 2 oz. Spiced Rum, 1 oz. of your prepared Apple Syrup, .75 oz. Lemon Juice, 1 egg white, 1 dash Orange Bitters, and 1 dash Angostura Bitters. Dry shake (without ice) for 30 seconds. Add ice to the shaker and shake vigorously until the mixture is foamy and well chilled. Strain the cocktail into a Nick and Nora glass or a coupe glass. Garnish with a dehydrated apple or an apple slice.