Step 1.
- Chill a martini glass by filling it with ice water and setting it aside.
Step 2.
- In a cocktail shaker, add ice, gin, blood orange juice, and dry vermouth.
Step 3.
- Shake well until the mixture is chilled.
Step 4.
- Empty the ice water from the chilled martini glass.
Step 5.
- Strain the cocktail mixture into the chilled glass.
Step 6.
- Garnish with a slice of blood orange on the rim.