Step 1: Make the Berry Sauce

1. Cook the frozen berries in a saucepan over low-medium heat, stirring frequently.
2. Mash the berries with a potato masher and cook until thickened. For a smooth sauce, strain through a sieve to remove seeds.
3. Chill the sauce in the refrigerator until ready to use.

Step 2: Make the Cream Base

1. In a mixing bowl, beat the heavy whipping cream until stiff peaks form.
2. In another bowl, mix the sweetened condensed milk and vanilla extract until smooth.
3. Fold the whipped cream into the condensed milk mixture in two additions until fully combined.

Step 3: Assemble and Swirl

1. Pour half of the cream mixture into a loaf pan or freezer-safe container.
2. Drizzle half of the berry sauce over the cream and swirl gently with a knife.
3. Repeat with the remaining cream and berry sauce to create layers.

Step 4: Freeze and Serve

1. Cover the container with foil or a lid and freeze for at least 6 hours or overnight.
2. Let the ice cream sit at room temperature for 5 minutes before scooping. Enjoy!