- Place half a can of sweetened condensed milk, 1/4 cup lime juice, and frozen mango (4 cups) in a food processor, and blend until smooth.
- Transfer the mixture to a loaf pan or small casserole dish and spread out in an even layer.
- Place the remaining sweetened condensed milk, lime juice (1/4 cup), and frozen raspberries (4 cups) in the food processor, blend until smooth. Dollop heaping spoonfuls over the mango layer.
- Using the spoon, swirl the raspberry mixture into the mango, creating a marbled look (being careful not to overly stir the two mixtures together).
- Cover and freeze until firm, about 6 hours to overnight.
- Once firm, scoop and serve the sherbet. Garnish (optional) with mango slices, raspberries, and lime slices.