Add oil to pan, add the chopped leek. Fry until they soften. Add chopped carrots, chopped mushrooms, and garlic.
Add any fresh herbs, Pulses and stock. Bring the mixture to boil then lower to reduce the liquid quantity.
Preheat the oven to 200/180/ or Gas 6.
Boil the peeled potatoes until tender. Drain. Add milk and butter to mash until smooth.
Stir in Worcestershire sauce, soy sauce to vegetable mix. Season well.
Transfer the vegetables to an ovenproof dish. Spread the potato mash over evenly. Bake in the oven for 18-20 mins until golden brown.