Preheat oven to 350 degrees. Mix flour, sugar and salt together; set aside. Melt butter with unsweetened chocolate. Add to flour mixture and stir. Beat eggs until foamy. Stir eggs, vanilla, sour cream and chocolate chips into batter. Pour into oiled 9 x 33 cm baking dish. Bake for 30 minutes. Time carefully as toothpick test is unreliable. Cut into 4 cm squares. ENJOY!! Makes 48 brownies.