This soup is only as good as the strawberries you use. I recommend very ripe, small, home-grown strawberries rather than huge berries you find at the supermarket.
Place the strawberries and 2 Tbsp. of sugar in the bowl of a food processor or blender. Using short burst, puree the strawberries until almost smooth. Taste and add the remaining sugar, if needed (it just depends how sweet your berries are to start with). Add lemon juice and Grand Marnier and pulse to combine.
Place a fine mesh strainer over a medium bowl. Pour the strawberry soup through the strainer, gently helping it through with a rubber spatula, to remove (most) of the seeds. Cover and chill for at least an hour before serving.
Place a scoop of ice cream in a chilled bowl and surround with the chilled strawberry soup. Slurp it up and wish strawberry season lasted through the year.
Notes
* I quarter the berries to give my food processor a head start. If you over-blend the soup, it becomes pink and foamy which is not the look I'm going for!
** Leftover strawberry soup is great for breakfast with plain yogurt in place of the ice cream.
Recipe by strawberryplum at http://www.strawberryplum.com/chilled-strawberry-soup-with-vanilla-ice-cream/