½ vegetable stock cube (or just salt if you don’t have stock cubes)
1 egg, lightly beaten
2tbsp plain flour
375g puff pastry (I used shop-bought)
Boil the brown lentils in plenty of water, until just tender (probably around 20 minutes).
Meanwhile, heat the oil in a frying pan, and add the onion and garlic. Cook over a medium-low heat for several minutes, and then add the mushrooms and dried herbs. Season with black pepper and crumble in half a vegetarian stock cube (or just use salt).
When the mushrooms have released their liquid and all the vegetables are quite soft, remove from the heat and add the breadcrumbs. Also add the drained lentils once they’re cooked. Mix well, and then stir in the egg.
Heat the oven to 200°C (Gas Mark 6 / 400°F).
On a lightly floured surface, roll out your puff pastry – I used a ready-rolled sheet, but I still rolled it out a little thinner so that it measured around 15 x 10 inches. I then cut my pastry into two strips measuring around 7.5 x 10 inches. Your dimensions might be a little different, so just improvise if necessary.
Spoon the lentil mixture along the middle of each strip, pressing down lightly to help the mixture stick together. Roll each strip over the lentil mixture, sealing with a dab of milk.
Cut the two long sausage rolls into however many smaller rolls you would like – I cut each into 5, so I ended up with 10 rolls in total.
Place on a lightly greased baking tray (I also lined mine with baking paper), and brush each roll with a small amount of milk. Bake for around 25-30 minutes, or until puffed up and golden brown.