Best Cape Style Whole Wheat Bread

4 cups (480 g) whole wheat flour
1 cup (120 g) white bread flour
1 x 10 g packet instant dry yeast
1 T (15 ml) brown sugar
4 blocks of Weet-Bix, finely crushed
2 t (10 ml) salt
¼ cup (60 ml) sesame seeds or toasted sunflower seeds
2 cups (500 ml) lukewarm water
2 cups (500 ml) buttermilk at room temperature
2 T (30 ml) canola or grape-seed oil and some extra seeds to sprinkle over the top.
Oil or butter a 28 cm x 11 cm bread pan. Line the base with a strip of baking or buttered greaseproof paper.
Measure the two kinds of flour into a large, sturdy mixing bowl. Add the yeast and sugar. Crush the Weet-Bix in a plastic bag with a meat mallet or small saucepan and add to the flour. Add the salt and seeds and stir to blend.
Make a hollow in the flour and add the lukewarm water, buttermilk and oil. Stir with a strong wooden spoon until the mixture is very well blended. Add a little more water if the mixture is too heavy to stir. Spoon the bread mixture into the prepared pan. Sprinkle with some extra seeds.
Leave in a warm spot (see Chef's tip) until the bread has nearly risen to the top of the pan. Halfway through the raising time preheat the oven to 200ºC.
Bake for 1 hour. Remove the bread from the pan 5-10 minutes before the time is up and continue baking without a pan for the final 5-10 minutes to crisp the bottom crust.