Keep the butter at room temperature till it softens a bit, but still hard enough to hold shape and get blended. Using a beater, beat the butter and then add condensed milk. Again beat till you get a creamy mix.
Sift the flour with baking powder, baking soda and keep it aside.
To the liquid add 3/4 cup flour, 3/4 cup cola and gently blend in to mix well.
Then, add the remaining quantity and combine. Do not over beat.
Pre-heat oven at 170 C.
Grease and dust a 8" square baking tray. Ensure the extra flour is removed.
Pour the batter into the tray. The consistency is dropping state, gently pat it down using the spatula or pat it down.
Bake the cake for 30 minutes or until a tooth pick comes out clean.
Remove from oven and let it cool for 5 minutes.
Invert on to the wire rack and allow it to cool completely before slicing.