Split the bread in half, reserve the top for another use. Place the base cut side up onto an oven tray. Combine the butter and mustard and brush over the Turkish bread. Top with prosciutto and tomatoes. Drizzle with the oil sachet and sprinkle with salt sachet from the Mix-a-Mato® tomatoes. Scatter over the brie then sprinkle with gouda.
Cook under a medium-hot grill for 3-5 minutes until the cheese has melted.
Meanwhile, combine all the herby mayo ingredients in a blender or small processor. Blend until smooth. Drizzle the mayo over the melt, top with rocket. Cut into pieces to serve.