In a medium saucepan, heat heavy cream, milk, 6 Tbsp sugar, salt and seeds of 1/2 vanilla bean along with vanilla bean pod over medium heat. Bring mixture just to a gentle bubble, stirring occasionally (remove from heat as necessary to prevent vigorous boiling while preparing remainder).
Meanwhile, in a mixing bowl, whisk together egg yolks and 2 Tbsp sugar until well blended. Add cornstarch to egg yolk mixture and mix until very well combined and and slightly pale and fluffy. Take about 1/2 cup of the hot cream mixture from pan, and while vigorously whisking, slowly pour hot cream mixture (about 1 Tbsp at a time) into egg yolk mixture.
Reduce burner temperature to medium-low. Then, while whisking hot cream mixture in saucepan, slowly pour egg yolk mixture into hot cream mixture in saucepan. Cook mixture, whisking constantly, until thickened (allow it to boil for about 30 seconds to cook out starchy flavor). Immediately force mixture through a fine mesh strainer into a bowl. Mix in 1 Tbsp butter. Cover with plastic wrap pressing directly against surface of custard. Chill thoroughly, about 2 hours.
For the cupcakes:
Preheat oven to 350 degrees. In a mixing bowl, whisk together flour, baking powder and salt for seconds, set aside. In the bowl of an electric stand mixer fitted with the paddle attachment, whip butter and granulated sugar until pale and fluffy.
Mix in egg then blend in egg whites and vanilla. Add 1/2 of the flour mixture and blend just until combined, then add milk and blend just until combined and finish adding in remaining 1/2 flour mixture and blend just until combined.
Divide batter among 12 paper lined muffin cups, filling each cup about 2/3 full. Bake in preheated oven 21 - 24 minutes until toothpick inserted into center of cupcake comes out clean. Transfer to a wire rack to cool completely.
To assemble cupcakes:
Pipe or spread chilled pastry cream over cooled cupcakes into an even layer. Working with one cupcake at a time, sprinkle entirety of pastry cream with sugar then heat with a kitchen torch until sugar begins to melt and caramelize*.
Allow topping to cool then garnish with whipped cream and a raspberry if desired. Serve immediately (note: the pastry cream can be made the day before and the cupcakes can be made hours ahead of time but top with sugar and caramelize sugar just before serving).
*I would first coat the edges of pastry cream while rotating the cupcake, then sprinkle tops, then I would torch it and add another layer of sugar. I just found working in layers worked best so it didn't all bead up and just run off the sides, but just experiment and see what works best for you. I used about 1 - 1 1/2 tsp sugar per cupcake.
Recipe Source: vanilla cupcake adapted from Sprinkles Cupcakes via Oprah, pastry cream lightly adapted from Cook's Illustrated