Chop 12 of the strawberries into ½-in/1-cm cubes. Reserve.
Combine the remaining strawberries, 7 oz/200 g sugar, 8 oz/230 g of the water, and the lemon juice in a nonreactive saucepan and bring to a boil. Simmer for 2 to 3 minutes until the strawberries are heated through and just starting to break down.