Perhaps if they are in crumbs, you could use them as the base for a fruit crumble. Just put apples, rhubarb or whatever fruits you like in the bottom of a dish. Put the crumbled biscuits on top with a spoonful of demerara sugar and dot with a little butter, put in the oven until the fruits are cooked (topping won't need long, because it's already cooked).
Then smother in custard or double cream to disguise the taste of the baking soda...!!