Boozy Watermelon Mint Lemonade

Bahan-bahan (4 porsi)

• 2 1/2 pounds watermelon flesh, seeds removed, cut into chunks
• 1/4 cucumber, cut into chunks, plus slices to garnish
• 1 cup fresh lemon juice, plus an additional lemon, sliced, for garnish
• 1/4 cup packed mint leaves, plus more mint, for garnish
• 2 1/2 cups white rum, vodka, or water
• 1/4 - 1/2 cup agave syrup or simple syrup