Prick potatoes and bake in middle of oven 1 1/2 hours, or until very soft. Scoop flesh into a bowl and beat in remaining filling ingredients with salt to taste. Filling may be made 2 days ahead and chilled, covered.
Reduce oven temperature to 425°F.
In a small bowl stir together butter and curry powder. Put 1 phyllo sheet on a work surface with long side facing you. Brush left half of phyllo with some curry butter and sprinkle with about 1 teaspoon peanuts. Fold plain half over and fold in each end to make an 8-inch square. Brush top with curry butter and sprinkle with about 1 teaspoon peanuts.
Arrange phyllo in an 8-inch square baking pan. Fold butter, and sprinkle 2 more phyllo sheets in same manner, arranging them in baking pan as prepared.
Spread filling on bottom crust. Fold butter, and sprinkle remaining 3 phyllo sheets in same manner, arranging over filling to form top crust and inverting last sheet so that folded-over phyllo is on underside.
Bake sweet potato mixture in middle of oven 20 minutes, or until crust is flaky and golden, and cut into squares.