1. Preheat your oven to 180°C/Fan 160°C/Gas 4. Fill and boil your kettle. Peel and finely chop the onion. Tear or chop the mushrooms into small pieces.
2. Place a medium-sized pan on a medium heat and add 1 tbsp olive oil, the onion and mushrooms. Season with salt and pepper. Fry, stirring occasionally, for 6-8 mins till the veg are glossy and starting to soften.
3. While the veg fry, fill a large pan with hot water from the kettle. Add a big pinch of salt, cover and set on a high heat to come back to the boil. When the water is boiling, add the pasta and simmer for 8 mins till the pasta is tender but still with plenty of bite. Drain and set aside.
4. When the veg are glossy, add 3 tbsp flour to the pan and cook, stirring, for 2 mins. Add a splash of almond drink – around 50-100ml. Cook, stirring, till the almond drink is combined smoothly with the veg and flour. Continue adding the almond drink, a splash at a time and stirring to incorporate. Once all the almond drink is added, let the white sauce bubble up, then turn the heat down and simmer for 3-4 mins, stirring occasionally, till the sauce has thickened slightly.
5. While the sauce cooks, halve the cherry tomatoes. Add the cherry tomatoes and baby leaf spinach to the white sauce. Stir to mix and wilt the spinach. Add 1 tbsp nutritional yeast and the pasta and stir to mix. Taste and add a pinch of salt and pepper, if you think it needs it.
6. Scoop the pasta and sauce into an ovenproof dish. Sprinkle over the breadcrumbs and slide the dish into the oven. Bake for 20 mins till golden and bubbling. When it's ready, take out of the oven and cool for 2-3 mins before serving.
7. What Is Nutritional Yeast?
Dried nutritional yeast is what gives this vegan version of mac & cheese its 'cheesiness'. The yeast is grown, usually on something like molasses, then harvested and heat treated to deactivate it, so it won't ferment. You can't bake bread or make beer with it, but you can use it to add a rich, parmesan-like flavour to dishes.