Preheat oven to 350. Lightly grease and flour a 9 inch round springform cake pan.
To make base, melt butter and chocolate in pan over low heat, stirring frequently, til smooth. Remove from heat and beat in sugar. Add eggs and milk, beating well. Stir in flour, mixing just til blended. Spoon into prepared pan, spreading evenly. Bake in preheat3ed oven for 25 minutes. Remove from oven and reduce oven temperature to 325
For topping, beat together cream cheese, sugar, eggs and vanilla extract til well blended. Stir in yogurt, then pour into pan. Bake for another 45 to 55 minutes or til center is almost set. Run a knife around edge of cheesecake to loosen from pan. Let cool before removing form pan. Chill in refrigerator for 4 hours or overnight before cutting into slices. Drizzle with melted chocolate and serve with chocolate dipped strawberries.