Preheat oven to 180ºC . Grease and flour 9x12 inch pan. Melt butter and chocolate in a double boiler over boiling water. Set aside to cool. Beat eggs and sugar until thick and lemon colored. Add vanilla and jam. Fold chocolate into eggs and mix thoroughly. Gently fold sifted flour into batter, mixing just until blended. Pour into prepared pan and bake for 25 minutes or until center us just set. Do not overbake. (of course, these are great on their own too!) These are my own creation using several other recipes for inspiration.
Also see the recipe for Raspberry Brownie Cheesecake