Heat oven to 350 degrees. In a small saucepan, bring 1 1/2 cups water to a boil. Turn off heat, add chopped papaya and pineapple to water, and cover pan. Let sit until fruit is softened, about 10 minutes. Strain the liquid, reserving 1/2 cup; set fruit and reserved liquid aside to cool.Advertisement
Butter and flour two 5-by-2 1/2-inch loaf pans or one 8 1/2-by-4 1/2-inch loaf pan; set aside. In mixing bowl, combine flour, baking powder, baking soda, salt, and allspice; set aside.
In the bowl of an electric mixer fitted with the paddle attachment, combine melted butter, sugar, egg, vanilla, reserved fruit, and reserved soaking liquid on medium speed. Add reserved flour mixture, and mix until smooth. Pour batter into prepared loaf pans; smooth tops with spatula. Bake until golden brown, about 40 minutes for small loaves, or about 50 minutes for large loaf. Transfer to a wire rack to cool 5 minutes. Slide a knife around sides of loaves inside pans, then turn loaves out onto rack; let cool. Loaves will keep wrapped in plastic wrap for 2 days at room temperature or in the freezer for up to 2 weeks.