Combine evaporated milk, egg yolks, brown sugar, and spices in top of double
boiler. Using a wire whisk beat the ingredients until smooth. Place top over simmering
water and cook until custard thickens, stirring constantly.
Remove from heat.
Stir in 1 cup pumpkin puree. Set aside.
In medium-size bowl beat egg whites, salt, and cream of tartar until stiff peaks
Fold beaten egg whites into pumpkin custard.
Scrape into freezer container
or serving dish, cover tightly, and freeze until firm (about 3 hours).
Serve directly from freezer (doesn't have to ripen in refrigerator first).