Maple Whiskey Sour

Bahan-bahan (1 porsi)

• 2 ounces whiskey
• 1 egg white* (optional)
• 1 ounce freshly-squeezed lemon juice (or other citrus juice)
• 3/4 ounce maple syrup
• 2 -3 shakes Angostura bitters (optional)
• ice