In one bowl, add the white bread flour and half of the other dough ingredients. In a second bowl, add the spelt flour and the rest of the other dough ingredients. Mix both portions thoroughly until a dough forms and then knead each separately till smooth, about 10 minutes. Cover and set aside in a warm place until the dough has expanded to twice the size, about 1 to 1.5 hours.
Knock both portions back and then divide each into two equal portions. Roll them by hand into four long 'sausage' shapes. Pinch the four 'sausages' together at one end and splay the other ends out.
This plait is made with four strands. An even number plait is a little more complicated than an odd number. I have shown the strands labelled. Each length takes the letter of its position.
Lay A over B and C. Move B and C to the left to become the new A and B.
Lay D over B and C.
Alternately repeat steps 4 and 5 until the end of the loaf is reached. Pinch the ends together and tuck under. Cover and allow a second rise for about 1 hour.
Preheat the oven to 180 C / 160 C fan / Gas 4. Place a shallow tin of water on the base of the oven; this helps with making the crust nice and crispy.
Brush the loaf with the beaten egg and sprinkle with poppy seeds if desired. Bake in the preheated oven until the base sounds hollow when tapped, about 20 to 25 minutes.
Instead of two colours of dough you could also add different flavours to each portion such as sun dried tomatoes, chopped olives or pesto.