Vegan cottage pie with sweet potato mash

2 carrots or parsnips

100g green beans 

3 tins of cooked Puy lentils, or other green or brown lentils 

6 sprigs of fresh thyme 

2 bay leaves a pinch of salt 

3 tablespoons tamari/soy sauce 

750ml veg stock 

½ teaspoon ground black pepper 

For the mash:

750g sweet potatoes 

250g potatoes 

1 tsp salt 

100ml milk 

a pinch of ground black pepper 

For the coriander cream:

100g cashew nuts 

65ml water 

15g fresh coriander 

1⁄3 teaspoon garlic powder 

½ teaspoon salt 

1 teaspoon balsamic vinegar