Add the Campari, gin, sweet vermouth, lemon juice, simple syrup, and egg white to an empty cocktail shaker.
Shake well (dry shake), then add ice, and shake again until well chilled.
Strain into a cocktail glass and garnish, if desired.
Notes
Make sure that you “dry shake” first before adding ice. This will make a fluffier and silkier texture for the egg white foam top.How to Make Simple Syrup in the Microwave:
Add 1 cup of water to a glass pyrex measuring cup. Microwave on high for 2-3 minutes or until piping hot. Add 1 cup of granulated sugar and whisk until dissolved.
Allow to cool and pour into a jar or glass bottle. The spout on the glass pyrex measuring cup helps with pouring without making a mess.