1. In a small saucepan on the stove, combine the strawberries, water (if using fresh) and granulated sugar. Allow the mixture to come to a boil then reduce to a simmer for 10-15 minutes (20 for frozen strawberries). Remove the saucepan from heat. Use an immersion blender to blend strawberries to a puree, or transfer the mixture to a high powered blender and blend until smooth. Measure out 1 1/2 cups of the puree and set aside to cool.
2. In a large mixing bowl fitted with the whisk attachment, or using a handheld electric mixer, blend the heavy cream until stiff peaks begin to form. Add the cooled strawberry puree and blend again on high until thickened up again.
3. Empty the condensed milk into the strawberry whipped cream and use a spatula to fold everything together until there are no white streaks left. Empty the mixture into a freezer-safe container and smooth it out with a spatula. Place the ice cream into the freezer for 5-6 hours before serving.

Leftover ice cream can be stored in an airtight container in the freezer for up to 2 months. It will get harder/more crystallized over time!