Start by sterilizing your glass jars (if you will store for a few days).
Wash the strawberries. Cut the stems off 10 strawberries (this is for the puree).
Place the 10 in a mixing bowl. Thoroughly mash them with a fork or heavy utensil. Once its thoroughly mashed, mix in the Sugar (3 Tablespoons). Set aside.
Then finely dice 5 additional strawberries (this is for the toppings)