In a bowl whisk egg yolks and 1/2 cup sugar until it is a pale yellow, set aside. In a medium saucepan heat heavy cream, over low heat, to just a boil. Slowly add cream to yolks, whisking constantly to avoid curdling. Transfer yolk mixture back to saucepan. Cook until custard thickens and coats the back of a spoon, then add vanilla and whiskey. Keep custard over low heat to keep warm, but do not allow eggs to curdle. In a clean medium bowl whisk the egg whites, remaining 1 tablespoon of sugar, cream of tartar and salt until stiff peaks form. Drop heaping spoonfuls of the meringue onto a parchment lined baking sheet. Bake 8 minutes, or until peaks are golden. To assemble, divide custard into 4 shallow bowls. Top each with a meringue peak, sprinkle with berries and powdered sugar.