Heat the oven to 200°C/Fan 180°C/Gas 6.Halve the butternut squash. Scoop the seeds out of one half. Peel and chop it into small chunks. Spread out on the baking tray. Drizzle with a splash of olive oil. Season. Roast in the oven for 20-25 mins till tender and caramelised. Shake half way through.
Fill the kettle and boil it. Trim, rinse and shred half the cabbage. Discard any thick stems. Rinse the leeks. Finely slice them. Rinse and pat dry 2 sprigs of rosemary. Finely chop the leaves from the sprigs.
Fill a large pan with hot water from the kettle. Add a pinch of salt. Pop the cabbage in the pan. Simmer for 3 mins till just tender. Lift out of the pan with a slotted spoon. Pop in a colander. Keep the hot water in the pan for later.
While the cabbage cooks, pop the flaked almonds into a frying pan. Toast over a medium heat for 2-3 mins till golden. Keep shaking the pan while they cook so they brown evenly. Tip into a bowl.
Warm a splash of olive oil in the frying pan. Add the leeks. Season. Fry over a medium heat for around 5 mins till soft and golden. Stir occasionally while they cook.
Add the spaghetti to the pan of hot water from earlier. Cover. Simmer for about 8 mins till the spaghetti is cooked but not too soft. It should still have a little chew to it.
Add the drained cabbage to the leeks. Stir and fry gently for about 5 mins till the veg is golden brown around the edges. Stir the rosemary and roast squash into the frying pan with the rosemary.
Drain the spaghetti and toss with the veg to mix. Serve topped with spoonfuls of ricotta and the toasted almonds.