In a blender, combine hulled and sliced fresh strawberries, Cointreau liqueur, Arrogante Reposado tequila, and Grenadine. If possible, use grenadine syrup prepared without artificial flavors such as Sonoma or Stirrings. They are less sweet and have more pronounced authentic pomegranate flavor, so your cocktail will be more delicious.
Pulse several time to puree the strawberries. Start adding the ice, several pieces at a time, and blend until the cocktail's consistency is smooth and thick.
Pour the drink in the chilled rocks glass and serve with a straw. Garnish with a strawberry.