Add the frozen pineapple chunks, pineapple juice, ice cubes, and fresh mint leaves into the blender.
Secure the lid and blend on high speed until the mixture is smooth, thick, and icy, with a slushy consistency. This should take about 30-45 seconds, and you should see the ingredients transform into a frosty, semi-cream texture.
Stop the blender and check the texture. If it's too thick, add a splash more pineapple juice and pulse briefly to incorporate. If too thin, add a few more ice cubes and blend again until desired consistency is achieved.
Pour the slushie into chilled glasses, allowing some of the frosty mixture to mound at the top for an appealing presentation.
Garnish each glass with a sprig of fresh mint for a fragrant, vibrant touch.
Serve immediately with a straw, and enjoy the cooling, tropical flavors of this refreshing slushie.