Combine all ingredients in a shaker and shake with ice. Strain into an ice-filled glass and garnish with nutmeg.
1 lb. hazelnuts
3 cups turbinado or demerara sugar
1 1/2 cups water
4-5 dashes rose water
Heat oven to 400 degrees F. Coarsely crush hazelnuts in a bag with a mallet or pulse briefly in a food processor. Place crushed hazelnuts on a baking sheet and toast in the oven for 5 minutes, shaking several times. Place toasted nuts, sugar and water in a medium pot and bring to a low boil. Reduce heat and simmer for 5 minutes. Remove from heat, cover and refrigerate overnight. Strain through a cheesecloth-lined strainer into a clean glass bottle. Add rosewater and stir.