Mango Muffins

8 tbsp. unsalted butter, at room temperature
1/4 cup Cornflakes crumbs
3/4 cup light brown sugar
3 eggs
2 cups sifted all-purpose flour
1 tbsp. baking powder
1 tsp. salt
2 mangoes, peeled, pit removed, cut into 1/2 inch cubes (about 2 cups)
1-1/2 cups coarsely chopped walnuts or pecans
2 tbsp. dark rum
1 tsp. grated lime zest
Preheat oven to 400 degrees. Lightly coat 24 muffin tins with 2 tablespoons of butter, or with non-stick cooking spray, or line them paper baking cups. If not using paper liners, sprinkle with Cornflakes crumbs; tap out excess. Stir and toss together the flour, baking powder, salt until completely mixed. Place the remaining 6 tablespoons of butter in a large mixing bowl and beat either by hand or with electric mixer until light and fluffy. Gradually beat in sugar. Add eggs, one at a time, beating well after the batter is blended; it should not be completely smooth. Fold in mangoes, walnuts, rum and lime zest. Spoon batter into prepared muffin cups, filling 2/3 full. Bake for about 20-25 minutes, until tops are golden and a toothpick inserted in the center of a muffin comes out clean. Cool in pans on wire racks for 5 minutes before removing from pans.