Begin by melting the white chocolate chips. Place the white chocolate chips in a microwave-safe bowl and heat in 30-second intervals, stirring in between, until melted and smooth. Alternatively, you can melt the white chocolate chips using a double boiler on the stovetop.
Take a martini glass and gently dip the rim into the melted white chocolate, twisting the glass to coat the outer edge with chocolate.
Immediately dip the chocolate-coated rim of the glass into the crushed graham crackers, gently pressing the graham crackers to adhere to the chocolate. Rotate the glass to cover the entire rim with the crushed graham crackers.
Set aside the rimmed glass to allow the chocolate and graham crackers to set.
Repeat this step for the remaining martini glasses.
In a cocktail shaker, add some ices, vodka, lime juice, sweetened condensed milk, and caramel syrup or simple syrup (if using).
Shake the mixture vigorously for about 15-20 seconds to combine and chill all the ingredients.
Strain the mixture into the rimmed martini glasses.
Garnish each martini with lime slices, whipped cream, graham crackers or crushed graham crackers.
Serve and enjoy your Key Lime Pie Martini!