Meat-free shepherd's pie

Shepherdess pie? No idea. Yummy, though.

Made it up myself but it turned out to be kind of similar to BBC Good Food's version. A good user-upper recipe. Properly vegetarian if you use the right cheese, stock, and an alternative to worcester sauce (marmite?).

1 onion, diced
1 clove garlic, smashed
1-2 large handfuls mushrooms, chopped to a mix of sizes
a few going-soft cherry tomatoes (optional)
stick of slightly limp celery* (optional)
2-3 carrots,* diced large
1 tin green lentils, drained
handful frozen peas
2 med-large sweet potatoes, peeled and cut into chunks
grated cheese, amount to taste (I used mature cheddar)
1-2 tsp dried cumin
salt to taste
1 tsp dried thyme
stock cube of choice
worcester sauce

* rescue soft celery and carrots in cold water overnight (I stand mine in a pint glass in the fridge door, and try not to pour them on my cereal in the morning...)

Soften onion, celery, garlic with thyme and tomatoes, covered to retain moisture. After ~5 mins add the carrot and lentils, and leave covered to cook until the carrot is just starting to soften.
In a separate pan, cook the sweet potato for ~15 mins until soft and mashable.
In another separate pan, cook the mushrooms with the stock cube (crumbled/chopped) and a splash of worcester sauce. Cover them and cook until they shrink and yield their liquid. Add the mushrooms and liquid along with the peas to the onion mixture and leave to simmer while you mash the sweet potatoes with salt and cumin. Layer the lentil mix and the mash in an oven dish, top with grated cheese, and cook for 20 mins at 180°C.