HEAT oven to 325°F. Grease and flour 8 inch square baking pan.

MELT butter and 3 squares chocolate together over low heat or in microwave on MEDIUM for 2-3 minutes.

BEAT eggs until foamy in a large bowl. Gradually add sugar, beating at high speed until lemon coloured. Stir in melted chocolate mixture. Add flour and salt; mix at low speed until just combined. Chop remaining chocolate and stir into flour mixture.

SPREAD half of batter into prepared pan.

HEAT jam in microwave on MEDIUM for 2 minutes. Spread jam evenly over batter. Add spoonfuls of remaining batter over jam and zigzag knife through batter to marble.

BAKE for 30 - 35 minutes or until toothpick inserted in centre comes out clean.