Line a small 4 1/2 x 2 1/2 x1 1/2-inch loaf pan with parchment paper or greased wax paper to prevent sticking.
Sift the dry ingredients into a bowl, rub in the fat until the mixture resembles fine breadcrumbs and then stir in the sugar if used.
Add the milk and mix to a soft dough.
Turn into the prepared pan and spread evenly.
Bake in the center of a hot oven (425°F) for about 30 minutes or until firm to the touch.
Turn out onto a cake rack, remove the paper and leave to cool.
Use like yeast bread.
Mix together the following ingredients and sift 2-3 times: % cup cornstarch, 1/8 cup baking soda, 1/2 cup cream of tartar, 2 oz tartaric acid (available from pharmacies).
Store in a clearly labeled airtight container in a dry place.