Blend berries and sugar together in a food processor or blender until smooth, scraping down sides of bowl if needed. Transfer berry mixture to a bowl.
Beat sweetened condensed milk and vanilla extract together in a bowl using an electric mixer until light and fluffy; fold into berry mixture. Pour mixture into a shallow pan and freeze for 1 hour; stir and return to freezer, 8 hours to overnight.
Remove from freezer and let stand 10 to 15 minutes before serving.