Heat your oven to 200°C/Fan 180°C/Gas 6. Halve the butternut squash. Scoop out the seeds. Pop the squash on a baking tray, cut-side up. Bake for 40 mins till the squash is tender.
Peel and finely chop the onion. Trim and dice the courgette. Halve the peppers. Scoop out the seeds and white bits. Roughly chop them. Peel and grate or crush the garlic. Finely chop the leaves from 2 rosemary sprigs.
Warm 1 tbsp oil in a deep frying pan. Add the onion. Season with salt and pepper. Stir and fry over a medium heat for 5 mins till soft. If it looks like it’s sticking, add a splash of water. Stir in the garlic and rosemary. Cook and stir for 1 min.
Add the courgette and peppers to the pan. Cook and stir for 5-8 mins till the veg are soft. Stir every so often. Take off the heat.
Take the squash out of the oven. Drain off any water. Scoop out the flesh so you have a shell around ½ cm thick left in the skin. Add the squash to the veg in the pan. Stir to mix together. Taste and adjust the seasoning.
Spoon the veg into the squash shells. Slide the tray back into the oven. Bake for 20 mins till golden.
While the squash finishes cooking, wipe the frying pan clean. Tip the flaked almonds into the clean, dry frying pan. Toast for 2-3 mins till golden brown. Tip into a bowl.
Whisk the balsamic with ½ tbsp oil and some salt and pepper. Toss with the salad leaves to dress them. Serve the roast squash with the salad leaves, scattered with the toasted almonds.