1. Prepare the Crust:

1. For the raspberry ripple: In a small saucepan, combine raspberries, sugar, water, and lemon juice. Cook over medium heat for 5-7 minutes, until the berries break down and the sauce thickens slightly. Press through a fine-mesh sieve to remove seeds. Let cool completely.
2. In a large bowl, use an electric mixer to whip the cold heavy cream until stiff peaks form.
3. Gently fold the sweetened condensed milk and vanilla extract into the whipped cream until fully combined and no streaks remain.
4. Pour one-third of the ice cream mixture into a loaf pan. Drizzle with one-third of the cooled raspberry sauce. Repeat layers twice more.
5. Use a knife or spatula to gently swirl the sauce through the ice cream. Cover tightly with plastic wrap and freeze for at least 6 hours, or until firm.