Preheat the oven to 200°C (180°C fan) / 400°F / Gas Mark 6. Line a large baking tray with baking paper. Cut the tomatoes in half through the equator and arrange them cut-side up on the tray. Deseed the peppers and cut them into large flat pieces, then add them alongside the onion quarters and whole garlic cloves. Drizzle everything with the olive oil, sprinkle over the smoked paprika and cayenne, and season generously with salt and black pepper. Toss gently to coat — you should see the oil glistening on the vegetables.

Roast for 40–45 minutes, turning halfway. After 20 minutes, the kitchen will fill with a sweet, toasty aroma and the edges of the peppers will begin to char. Give the tray a shake and turn the larger pieces so they colour evenly. By the end of the cooking time, the tomatoes should look collapsed and wrinkled, the peppers soft and deeply caramelised in patches, and the garlic skins papery and lightly browned. The onions will be tender and translucent at the centre.

Remove from the oven and let everything cool for 5 minutes. This brief rest makes handling the garlic much safer — the cloves will be very hot and soft. Once cool enough to touch, squeeze the garlic cloves out of their skins into a large saucepan or Dutch oven. Add the roasted tomatoes, peppers and onions, scraping any sticky juices from the baking tray into the pan.

Add the stock and tomato purée. Pour in the 500 ml of stock and stir in the tomato purée and balsamic vinegar. Bring to a gentle simmer over medium heat — you'll see small bubbles breaking the surface. Cook for 5 minutes, stirring occasionally, to allow the flavours to meld. The liquid will turn a deep brick-red and the garlic will have completely dissolved.

Blend until silky smooth. Remove the pan from the heat. Using a stick blender, whizz the soup directly in the pan until it is completely smooth — this takes about 1 minute. If you prefer an ultra-silky texture, pass the soup through a fine-mesh sieve, pressing the solids through with the back of a ladle. Taste and adjust seasoning with more salt, pepper or a splash of extra balsamic vinegar. The soup should be thick enough to coat the back of a spoon but still pourable.

Serve hot, garnished with torn basil leaves and a drizzle of good olive oil. I like to ladle it into warmed bowls; the steam carries that gorgeous roasted fragrance right to your nose. For extra richness, add a swirl of coconut cream or a few toasted pumpkin seeds for crunch.