Sponge is made to activate the yeast and breakdown the sugar in whole wheat flour. Inorder to make the sponge, mix all the ingredients mentioned under the sponge and mix well for 2-3 mins. The gluten will begin to form and the mixture will be stringy. Set this aside for 30-60 mins until it has doubled (or tripled) up in size.
To this sponge mixture, add 2 cups of whole wheat flour along with salt and oil. If required, add 1 or 2 tbsp of warm water and mix it well. The dough should come together.
Now knead this dough until it is smooth and bouncy. When a piece of dough is stretched, it should not break for 2-3cms.
Place this dough in a well-greased bowl and cover it cling film.
Leave this in a warm place for 60-90 mins until it has doubled up in bulk. Gently punch it down and knead again for a min or two.
Now roll this dough into a rectangle (depending on the baking tin’s size) and fold the ends inside.
Begin rolling tightly from one side and seal it at the center.
Place it sealed side down in a greased (and lined) baking tin.
Leave it again for 30mins or more until the bread has doubled up.
Bake in a pre-heated oven at 180° C for 30mins until the bread is golden brown.
Let it cool down completely before slicing. Stays good for 3-4 days outside or a week in fridge.