Combine the yeast and milk in a large
bowl and leave to dissolve, about 15 minutes. Meanwhile, mash the
potatoes.
Add the potatoes, oil and salt to the
yeast mixture and mix well. Stir in the reserved cooking water, then
stir in the flour, in six separate batches, to form a stiff dough. Knead
until smooth, return to the bowl, cover and leave in a warm place until
doubled in size, about 1 - 1 1/2 hours.
Punch down, then leave to rise again
for 40 minutes.
Grease two 23 x 13cm loaf tins. Roll
the dough into 20 small balls.
Place two rows of balls in each tin.
Leave until the dough has risen above the rims of the tins.
Preheat the oven to 200oC/400oF/Gas
6. Bake the dough for 10 minutes, then lower the heat to 190oC/375oF/Gas
5.
Bake until the bases of the loaves
sound hollow when tapped, about 40 minutes.