In a blender add three (3) ice cubes, one (1) ounce of regular margarita mix, and pulse until you have crushed ice.
Spoon the crushed ice and margarita mixture into the bottom third of Mojito style glass. Place the glass in the freezer for fifteen (15) minutes.
Meanwhile, into the blender add one (1) scoop of vanilla ice cream, pineapple juice, the remaining ounce of margarita mix, two (2) tablespoons of crushed pineapple, and two (2) heaping tablespoons of Cool Whip.
Pulse until mixture is slightly mixed. If you mix until all of the ingredients are smooth you won't have the contrast of colors that make this cocktail visually appealing. However, if you do prefer to mix the ingredients well, then by all means mix until your heart is content.
Remove the glass with the ice and margarita mixture at the bottom and spoon in the ice cream mixture leaving the top third free.
Spoon in the remaining two (2) heaping tablespoons of Cool Whip, then garnish with 2 or 3 pineapple fronds that have been rinsed and patted dry.