Begin by chopping 1/2 cup of seedless watermelon into small cubes and placing them into a blender. Blend this mixture on high until smooth, which should take about 30 seconds. Once the watermelon is liquefied, strain the juice through a fine-mesh sieve into a bowl, discarding the pulp.

While your watermelon juice is being prepared, place a martini glass in the freezer. Allow it to chill for 15-20 minutes.

In a cocktail shaker, combine 1/4 cup of fresh watermelon juice, 2 ounces of vodka, and 1/2 ounce of orange liqueur, followed by 1 ounce of fresh lime juice and 1/2 ounce of simple syrup. Fill the shaker with ice.

Secure the top of your cocktail shaker and shake vigorously for 15-20 seconds.

Retrieve your chilled martini glass from the freezer and gently strain the cocktail mixture into it. Optionally, garnish with a watermelon wedge or mint leaves.