Preheat your oven to 200C (gas mark 6). Place cauliflower florets and squash bites in a large roasting tray and toss with olive oil, chili flakes, and a healthy pinch of sea salt flakes. Let them roast and set a timer for 20 minutes; this is when you need to add in the cabbage wedges.
While the veg are roasting, cut the red cabbage in wedges, small enough to handle with a fork later.
Toss with a bit of olive oil and salt again and add them in once your timer sets off.
It will be ready in ten minutes, 30-35 minutes from the initial cooking time.
For the dressing, squeeze a lemon, and keep some rind if you like. Combine with mustard, capers, honey, and olive oil. Drizzle over the warm veg when ready to serve.