You may use fresh, very ripe strawberries instead of frozen strawberries if that's what you have available. Just hull and dice them before mashing, and use a full 1 1/2 cups of water in which to cook them.
If desired, strawberry soda may be enhanced with a squeeze of fresh lime juice.
Strawberry syrup can also be used over vanilla ice cream, pound cake, waffles, pancakes, French toast, etc.
Adapted from AllRecipes.com