Preheat oven to 350°F. Spray bottom of each of 12 muffin cups with no stick cooking spray. Mix brown sugar and ginger in small bowl. Place about 2 teaspoons in bottom of each muffin cup, using all of the sugar mixture. Top each with 2 teaspoons chopped mango. Set aside.
Beat granulated sugar and butter in large bowl with electric mixer on medium speed until light and fluffy. Add eggs and vanilla; beat until well blended.
Mix flour, baking powder, garam masala and salt. Add alternately with milk to batter, ending with flour mixture and scraping bowl after each addition. Spoon evenly into prepared muffin cups.
Bake 20 minutes or until toothpick inserted in center comes out clean. Cool in pan 10 minutes. Unmold onto wire racks; cool completely.
Meanwhile, for the Honey Mango Coulis, heat mango nectar, honey and lemon juice in small saucepan on medium heat. Mix cornstarch and water in small bowl until smooth. Stir into nectar mixture. Stirring constantly, bring to boil. Reduce heat to low; simmer 20 to 25 minutes or until mixture is thickened. Stir in vanilla. Serve cakes, upside down, with Honey Mango Coulis. (If desired, slice off tops of each cake to make even surfaces.).