Place a metal loaf pan or other freezer-safe container in the freezer while you prepare the ice cream.

Add half of the fresh strawberries to a pot with the water, sugar, cornstarch, and 1 tsp of vanilla extract. Cook over medium heat until the strawberries start to break down and become mushy. Mash the strawberries as they cook with a fork or wooden spoon. Remove from heat and set aside to cool for 45-60 minutes.

Add the condensed milk and heavy whipping cream to a bowl and whip into soft peaks. Add the vanilla, lemon juice, and salt, then whip again until incorporated. Fold in the remaining fresh strawberries (uncooked).

Remove your container from the freezer, then transfer the ice cream mixture to the frozen container. Pour the strawberry syrup mixture on top of the ice cream mixture, then gently swirl it in, making sure not to mix it too much.