- Preheat the oven to 350 degrees. Grease a 9x5x3 inch loaf pan or 8x11x2 inch cake pan with 1 Tbs. of the butter.
- Drop the sweet potatoes into enough lightly salted boiling water to cover them completely and cook briskly until they are soft. Drain the potatoes thoroughly, then force the potatoes and banana through a ricer or food mill set over a deep bowl. Beat in the remaining 4 Tbs. of softened butter, add the eggs, and mix well. Add the Sugar, corn syrup, milk, evaporated milk, vanilla, nutmeg, cinnamon, coconut milk, and Raisins, and beat until the batter is well blended. Then pour it into the prepared pan.
- Bake in the middle of the oven for 11/2 hours, or until a cake tester or toothpick inserted in the center comes out clean and the top is golden brown.