The cupcakes were a big hit. I thought the frosting could have been better...but oh well...
The basic cake recipe was from here:
I modified it to include the mango, and made a double batch. I also tweak the egg proportions to make it a bit richer. Here's what I did.
In (my brand new) mixer with a paddle attachment, add 3 sticks of semi-soft butter and 2 1/2 cups of sugar, and beat till fluffy. In another bowl, mix 1 cup of milk (notice the reduction), 6 egg whites and 3 whole eggs, about 12 oz (less than half a tin) of Alphonso Mango pulp, 2 teaspoons vanilla (again notice the reduction), and 1 tablespoon ground cardamom. On a wax paper, mix 4 cups of AP flour, 4 tsp baking powder, 1/2 teaspoon salt. Alternate the milk and flour mixture to create a smooth batter in the mixer. Bake in big/small cupcake pans at 350. The small cupcakes took around 14-18 mins or so.
For the frosting:
(This is slightly different from what I did...but this is what I would do next time)
1 stick of softened butter + 1 package cream cheese + 4-5 cups of powdered sugar + 1 teaspoon vanilla + 1 teaspoon ground cardamom + 1/2 cup mango pulp. Beat until smooth and fluffy. I would only add more mango pulp as required to maintain the consistency and the taste.
Frost the cupcakes and garnish with pistachio powder.