Rinse the buckwheat under cold water, strain and set aside
Heat oil in a large non-stick pan and cook the garlic and leek over medium heat for around five minutes.
Add the sliced mushrooms and cook for a further five minutes.
Add the buckwheat, passata, olives, paprika, chilli and white pepper. Stir through until well combined.
Add a couple of ladles of stock (enough to just cover the other ingredients) and cook, gently stirring until all the liquid is absorbed.
Add more stock in similar amounts, stirring through until all stock has been absorbed. ( Take your time with this allowing the buckwheat to become tender but still firm enough to hold together). This should take around 25 min.
Once the buckwheat is tender and all stock has been absorbed, add the nutritional yeast, dill, parsley and lemon juice. Remove from heat and stir through. Add salt and pepper to taste.
Garnish with some fresh parsley or dill and serve immediately.