Preheat the oven to 200°C fan/425°F/gas 7. Line a baking tray with baking parchment.

Drain and rinse the lentils. Peel and finely chop the garlic, and peel and cut the onion into thin slices

Add 1 tablespoon of oil to a pan over a high heat. Once hot, add the sliced onion, a pinch of salt and a pinch of black pepper and cook on a medium heat for 5 minutes, stirring occasionally, until the onions are nicely browned and softened. Add the chopped garlic, maple syrup and balsamic vinegar, mix well to coat the onions, reduce to a low heat, and cook for 3–4 minutes, stirring regularly, until the onions are nice and soft and sticky. Add the drained lentils and tamari or soy sauce and cook for 3–4 minutes, stirring occasionally, to evaporate any extra moisture. Remove from the heat.

In a food processor or blender, add the cashews, and pulse until they reach a rough breadcrumb consistency. Add the onion-and-lentil mixture and 1⁄2 teaspoon of ground black pepper, and pulse until the mixture comes together but is not too smooth. You want to ensure there’s a slight bite to the filling. Taste and season with salt and pepper to your liking. Remove from the food processor and divide into 4 × 80g chunks, and then roll each into a sausage shape about 12–13cm long.

Roll out the puff pastry and cut into four even rectangles, about 12cm × 16cm. Place a sausage at one side of a pastry rectangle, 2–3cm in from the edge. Brush some oat milk along the other side, then roll the sausage up in the pastry until it overlaps and press gently along the seam to seal. Then place the sausage roll seam-side down and gently press down on it with the palm of your hand to help seal it more and to ensure it stays rolled when you bake it. Repeat with the remaining sausages and pastry.

Using a pastry brush, brush each sausage roll with a light coating of oat milk (this will help them to brown), then sprinkle with the sesame seeds, place on a parchment-lined baking tray and bake for 20 minutes, or until the pastry is golden brown.