6. Put a large roasting tin on the top shelf of your oven to heat up. Dissolve the stock cube in 500ml boiling water.
Halve, peel and thickly slice the onion. Cut the pepper into 2 cm thick strips, (discard the stem and seeds). Chop the stem off your chilli. Halve lengthways and de-seed.
Add the veg to the heated tin with the cherry tomatoes. Drizzle with 1 tbsp oil. Season. Roast for 20 mins till tender.
Dice the celery. Set a pinch aside for garnish. Peel and finely chop the garlic. Peel and grate 1 tsp horseradish. Add all but the celery garnish to the roasted veg. Stir. Put in a blender. Add the stock.
Roughly chop the parsley leaves. Add half to the blender. Grate in most of the lemon zest and squeeze in a little juice. Blend till smooth. Taste. Season. Add more horseradish, lemon juice or water if needed.
Serve topped with the remaining parsley, celery and lemon zest, a little grated horseradish. Drizzle each one with 1 tsp oil.