Have chopped white chocolate in a large bowl. Heat cream until hot but not boiling, pour over white chocolate. Let stand 1 minute then stir until smooth stirring in vanilla and salt. Refrigerate until completely cold, at least 4 hours or overnight. Don't whip until cupcakes are cool and ready to frost

Wkisk flour, baking powder and salt in a bowl, set aside

Whisk in another bowl milk and anilla and set aside

In another large bowl beat sugar and butter until light and fluffy

Beat in sour cream until smooth

Stir in flour alternating with milk in 3 additions

With clean beaters beat egg whites with cream of tarter until it holds stiff peaks . Fold into batter in 3 additions until blended

Divide batter evenly into prepared cupcake tins

Bake 17 to 20 minutes until a toothpick comes out just clean

Have 12 truffles unwrapped

Cut a slit in the top of each cupcake as soon as they come out of the oven. Press a truffle in each slit and gently press even with the top. Truffle will melt to cupcake. Remove from tins carefully and cool completely before frosting

Beat chilled cream and white chocolate until it it has soft peaks

Beat mascarpone, confectioner's 6 and 1/2 teaspoon vanilla until smooth

Stir iinto white chocolate mixture and beat until light and fluffy

Frost cupcakes with frosting, Store cupcakes, covered in refrigerator but serve at room temperature.Top each cupcake with some red and purple sprinkles a fresh raspberry before serving