Preheat the oven to 200°C/fan 180°C/gas mark 6. Put the onion wedges in a roasting dish and drizzle over 1 tbsp oil. Roast in the oven for 25-30 minutes, or until soft and starting to caramelise. Remove from the oven and leave to cool.
Meanwhile put the matzo crackers on a baking tray. Brush with the remaining oil and bake in the oven for 6-8 minutes, until golden brown. Remove from the oven and set aside.
Put the spinach leaves in a large bowl and add the onions, almonds and raisins. Break the matzo crackers into smaller pieces and toss through the salad.
In a small bowl, whisk together the date syrup and lemon juice. Season, then pour over the salad and toss. Serve immediately.