Mix the flours, potato starch, xanthan
gum, yeast, sugar and 1½ tsp salt in a
large bowl. Mix together the milk, oil and
vinegar in a separate bowl, then add to
the dry ingredients and mix until a soft
dough comes together. Cover loosely
with oiled cling film and leave to rise in
a warm place for 1 hr.
Knead in most of the seeds and walnuts.
Shape into a large round – oiled hands
will help. Roll the round in the remaining
seeds and nuts, then lift onto a baking
tray. Loosely cover again with oiled cling
film and leave for 1 hr more.
Heat oven to 220C/200C fan/gas 7. Bake
the bread for 15 mins, then reduce oven
to 190C/170C fan/gas 5 and continue
baking for 30 mins until the loaf sounds
hollow when tapped on the base. Leave on
a wire rack to cool, wrapped in a clean tea
towel – this will help to keep the loaf soft.