Welsh Rarebit Veggie Shepherd's Pie

Once your pan of water is boiling, add the potatoes and cook until you can easily slip a knife through, 15-20 mins.
Meanwhile, heat a drizzle of oil in a large frying pan on medium-high heat.
Once hot, add the mushrooms and stir-fry until browned, 5-6 mins.

Add the Worcester sauce to the mushrooms and allow it to evaporate, 1-2 mins. Stir in the garlic and sun-dried tomato paste, cook for 1 min more. Season with salt and pepper.
Pour in the tomato passata, red wine stock paste and water for the sauce (see ingredients for amount). Stir in the lentils, then bring the mixture to the boil. Simmer until thickened, 8-10 mins.

Meanwhile, grate the Cheddar cheese and pop it in a small bowl with the Dijon mustard (add less if you don't love mustard) and creme fraiche. Season with salt and pepper, then stir together and set aside.
Once the potatoes are cooked, drain in a colander and return to the pan, off the heat. Add a knob of butter (if you have any) and mash until smooth. Season with salt and pepper.

Taste the lentil filling and season with salt and pepper if needed.
Transfer to an appropriately sized ovenproof dish and top with an even layer of mash. Spoon the cheese and mustard mixture over the mash and spread it out with the back of a spoon.
Bake the pie on the top shelf of your oven until golden brown, 15-20 mins.