In a saucepan, melt 2 oz of chocolate and butter over a low heat and stirring constantly. Spread or brush over the bottom and up the sides of the pastry shell. Chill.

Meanwhile, in a mixing bowl, beat cream cheese, sour cream, sugar, and vanilla until smooth. Spread over chocolate layer, cover, and chill for 2 hours. Arrange strawberries, tips up, atop the filling. Brush jam over strawberries. Melt the remaining chocolate and drizzle over all.