Bring a saucepan of water to the boil and preheat the oven to 190C/Gas5
When the water is boiling drop in the gnocchi and cook for 2 minutes, then add the spinach and cook for a further 2 minutes; use a mug to scoop out 300ml of the cooking liquid; add the chicken stock powder to the mug, stir and set aside; drain the gnocchi and spinach
While the gnocchi are cooking, melt the coconut oil and butter in a large frying pan over a medium to high heat; when hot, add the chopped onion and leeks and fry for about 3 minutes or until the vegetables begin to soften; turn the heat to maximum and add the chicken and mushrooms to the pan; stir fry for a few minutes or until the chicken changes colour
Reduce the heat to just below medium and stir in the flour; stir fry for 1 minute then gradually add the stock, stirring in a quarter of the liquid at a time to avoid lumps
When all of the liquid has been added, bring to the boil, then take the pan off the heat and stir in the mustard powder, parmesan and chopped parsley; season with salt and pepper
Tip the drained gnocchi and spinach into the pan and gently stir everything together; tip the mixture into a baking dish, sprinkle the breadcrumbs over the top and then bake for 20 minutes or until the breadcrumbs are golden
Remove the dish from the oven and serve
4 servings