250ml whole milk, warmed to tepid
2 tsp active dried yeast
25g soft light brown sugar
400g strong white bread flour
100g rye flour
10g fine sea salt
100g butter, melted
1 egg, lightly beaten
A little butter or lard, for greasing
For the filling
About 250g spinach leaves or nettle tops, washed
1 tbsp olive oil
A knob of butter
1 onion, peeled and sliced
2 garlic cloves, peeled and thinly sliced
150–200g smoked ham, roughly chopped
100g hazelnuts, roughly broken
75g mature Cheddar, grated
2 tsp thyme leaves
Sea salt and freshly ground
For the dough, mix the warm milk, yeast and sugar together and whisk well. Leave for 15 minutes or so to froth up.
Combine the two flours and sea salt in a large bowl. Add the frothy yeast mixture, the melted butter and the beaten egg and mix to a rough dough. Turn out on to a floured surface and knead for around 10 minutes until smooth and giving. It’s a slightly sticky dough, so you may want to flour your hands. That said, try not to add any more flour than you absolutely have to. You can do this in an electric mixer fitted with a dough hook but I find it more satisfying to use my hands.
Put the dough into a clean, lightly oiled bowl, cover with a damp tea towel or clingfilm and leave in a warm place until doubled in size. This may well take as long as 4 hours because the dough is so rich – and it certainly won’t be risen sufficiently in less than an hour.
Meanwhile, for the filling, bring a large pan of water to the boil, add the spinach (or your greens of choice) and cook for 3–4 minutes or until the leaves are tender. Drain and, when cool enough to handle, squeeze out any excess liquid from the spinach and roughly chop it.
Heat the olive oil and butter in a large frying pan over a medium heat. Add the onion and cook, tossing occasionally, until it begins to soften and take on a little colour. Add the garlic, followed by the ham and cooked spinach, and cook for a further 2–3 minutes. Season well with salt and pepper, remove from the heat and allow to cool.
Grease a 35 x 25cm baking tray with butter. Carefully tip the risen dough out on to a well-floured surface and roll out to a rectangle, about 45 x 30cm, with one of the longer sides towards you. Brush the dough with a little melted butter or lard, leaving a 2–3cm margin at the longer edge furthest from you. Spoon the cooled ham and spinach mixture over the dough, spreading it as evenly as you can. Scatter over the hazelnut pieces. Season well with pepper and a good pinch of salt.
Now roll up the dough, starting at the long edge closest to you. Take your time as this can be tricky. Tidy up the ends of the roll by trimming them off with a sharp knife, then cut the roll into 12 equal pieces. Turn each piece on its side and arrange them in the greased tin so they all fit in. Scatter over the cheese and thyme. Carefully cover the tray with a damp tea towel, to stop the buns drying out as they rise. Leave them to rise in a warm place for 45 minutes–1 hour.
Preheat the oven to 200°C/Gas mark 6. Bake the buns for 20–25 minutes, until golden brown. Allow the buns to cool slightly before removing from the tin. Serve to friends with a full-flavoured bitter.