The fruit IS the ice cubes. And it's not really a margarita.
Macerate one quart of hulled strawberries in citrus (around the juice of two limes) and a tablespoon of sugar overnight, at least, stirring occasionally. Drink the delicious liquid that formed, then puree the fruit in a blender until it's as smooth as you can make it. Freeze in a somewhat shallow container.
For the drink:
Chip off several big chunks of strawberry puree and fit into a tall glass until full. Add:
- one big shot of blueberry vodka
- one big shot of grenadine
- top off with tonic water and a twist of lime.
Add a straw, and mash the melting strawberry chunks into your drink as you go.