Spinach and tomato loaf

Once, in a New England Winter, I saw a version of this festive bread; here is my attempt to re-create it.

Ingredients

200g frozen chopped spinach, de-frosted

100g tomato purée

300ml warm water

1 package dried yeast

60g salted butter, melted

1 ½ teaspoon salt

500g white bread flour, plus as much extra as necessary to form stiff doughs.

Method

1. Sprinkle dried yeast onto the warm water in a bowl, allow it to stand until yeast fully dissolved.  Add the melted butter and salt, then stir to mix well.
2. Squeeze as much water as possible from the spinach, add 75ml of the yeast mixture, and liquidise together. Stir in 100g of the bread flour, mix well.
3. In a different bowl, combine tomato purée and 75ml of the yeast mixture. Then add 100g of the flour, and mix well.
4. Into a third bowl pour the remaining yeast mixture, and add 200g of the bread flour.  Mix well, then add enough flour to make a stiff pliable dough. Knead well for 5-10 minutes until the dough is smooth and elastic. Put the dough into a bowl, cover and leave to rise for an hour.
5. Now add flour to the spinach mixture, until it forms a stiff dough. Knead well for 5-10 minutes and when this dough is smooth and elastic, put it in a bowl, cover and leave to rise for an hour.
6. Do the same with the tomato mixture.  Leave all three doughs in a warm place until they are risen and about doubled, or more, in size; about an hour.
7. Take each of the three doughs in turn and knead for a couple of minutes, then roll out each to an approximately 25cm square.  Using the plain white dough as a base, top with the spinach and then the tomato squares.  Roll the three layers together to make a large sausage shape, lay the loaf on a greased baking sheet with seam-side down, pinch the ends and tuck them under. Cover very lightly and leave to rise in a warm place for about half an hour.
8. While the loaf is rising, heat the oven to 200⁰ C; Gas mark 6; Fan oven 180⁰ C. When risen, brush the top of the loaf with egg-white, and bake for 35 minutes, or until the loaf sounds hollow when tapped on the underside.