Method

1. For the dough, combine flours, sugar and yeast in the bowl of a stand mixer fitted with a dough hook attachment. Stir to combine, then add margarine, egg and milk. Mix on a low speed until well combined. 

2. Increase to high speed and knead until a soft dough forms. Transfer to a greased bowl, cover and leave to proof in a warm place for an hour or until doubled in size. 

3. Meanwhile, prepare the leek filling. Heat olive oil in a frypan over medium heat. Cook the leek until softened. Add garlic and cook until fragrant. Season with black pepper to taste. Set aside to cool. 

4. Once the dough has doubled in size, punch the air out and place on a lightly floured surface.  

5. Roll the dough out into a 24 x 40cm rectangle. With the long edge closet to you, spread Marmite over the dough leaving a 2cm border on the top edge. Sprinkle over leek, cheese and herbs. Roll away from you to enclose the filling, pinching the seam to seal.  

6. Place the roll seam side down and cut in half lengthwise. Twist the halves together with the cut side facing up, then curl the braid around itself and place in a greased loaf tin. Cover and set aside for another 30 minutes or until almost doubled in size. Preheat oven to 180°C.  

7. Bake for 30 minutes or until golden brown, then cover with foil and bake for a further 30-40 minutes or until cooked through. Set aside for 10 minutes before transferring to a wire rack to cool. Serve warm or at room temperature.