Peel papaya, remove seeds and grate fruit on a box grater or food processor (yield 16 ounces grated pulp).
Cook fruit pulp for 15 minutes with butter and lime juice.
Add raisins and cashews, then cook about another hour on low heat, stirring frequently, until thick and somewhat dry and chunky and starts coming together in a ball (not like applesauce, but more like mashed potatoes).
Add vanilla and cardamom, stirring to mix.
Serve warm or cool, topped with a garnish of your choice.