Spicy Jalapeño Ginger Moscow Mule

Bahan-bahan (1 porsi)

• 2 ounces vodka
• juice from 1/2 a lime
• 1/3 cup grapefruit juice
• 1 -2 jalapeños or serrano pepper slices
• 1 -2 teaspoons fresh grated ginger
• 1 g inger beer, for topping
• candied rosemary, for serving ((optional))