Heat oven to 220C/fan 200C/gas 7. Put the vegetables into a large roasting tin, drizzle with half the oil and season to taste. Roast for 20 mins, turning once in a while until softened. Drizzle with the honey. Scatter the torn ciabatta and sunfl ower seeds over the top and return to the oven for a further 5 mins or until toasted.
Put the spinach into a large bowl and tip in the vegetables and ciabatta. Whisk the vinegar, mustard and remaining oil together, season to taste and toss into the salad until the spinach wilts slightly. Serve immediately.