In each glass, pour 1 tablespoon of strawberry syrup. Pour in 2 tablespoons gin and stir. Add 2 scoops ice cream and top with soda. Garnish with a strawberry.
In a small saucepan, combine all ingredients and bring to a boil over high heat, then reduce to a simmer over medium heat until strawberries breakdown and syrup thickens, about 20 minutes. Strain mixture, return to the saucepan, and reduce for 10 more minutes over medium heat, until syrup is thick enough to coat the back of a spoon. Chill until ready to serve.