Banana Bread

Whisk the first 4 ingredients in a bowl to blend. Combine the chocolate and walnuts in a small bowl; add 1 tbsp of the flour mixture and toss to coat. Beat the butter until fluffy. Gradually add the sugar, beating until well blended. Beat in the eggs, 1 at a time. Beat in the mashed bananas, lemon juice and vanilla. Finally beat in the flour mixture, until just smooth. Spoon 1/3 of the batter into a buttered and floured loaf pan. Sprinkle with half of the nut mixture. Spoon over 1/3 of the batter. Sprinkle with the remaining nut mixture and cover with the remaining batter. Run a knife through the batter in a zigzag pattern. Bake until tester inserted into the centre comes out clean, about an hour 5 minutes. Turn out onto rack and cool.