Put the peeled potatoes in a pot of cold water. Bring to the boil and then check to make sure they're cooked, usually after about 20 minutes. Drain them, then add one tablespoon of the fresh chopped herbs, some ground black pepper to taste and a little water. You can add two tablespoons of rice/oat/soya milk to the potatoes and then mash them, or just add the same amount of water and mash.
While the potatoes are cooking, place the drained black beans, lentils and split peas in a large pot. Add 725 ml of boiling water to the pot, cover it and then simmer for 50-60 minutes or until the pulses are soft and absorbed the water.
Prepare all the vegetables and then put them in another pot or a large frying plan with six tablespoons of water. Cook them gently for 10-15 minutes until they're softened and are turning gold at the edges. Add more water if you need to to stop them catching on.
Skin the tomatoes by placing them in a bowl and pour boiling water over them. Leave them for one minute, drain and carefully remove their skin. Then slice them.
Add the vegetables to the pulses then add the freshly chopped herbs, mace and cayenne pepper. At this point you can also grind some fresh black pepper into the veggies and pulses.
Spoon the mixture into the oven proof dish and then add the slices of tomatoes on top. After you've done this you can then spread the mashed potatoes on top of the tomatoes. Try not to add any salt at this stage, wait until you've tasted it and then add a little if you want.
Place the oven proof dish into the oven for about 20-25 minutes. I use a fan oven so you may need to keep it in a bit longer if you use a conventional oven.
Once the pie is cooked plate up onto warm plates and serve with your cruciferous vegetable of choice.