Heat oven to 350. In medium bowl stir together flour, sugar, 2 T. cocoa, milk, baking powder, salt and vanilla. Spread into greased 20 cm square baking pan. In medium bowl stir together remaining 4 T. cocoa, brown sugar and water. Pour over mixture in pan. Bake for 45 to 50 minutes or until pudding bubbles around edges. Remove from oven; let stand 20 minutes. Meanwhile, in small bowl stir jam until smooth. Drizzle each serving of warm pudding with jam.