Roasted Tomato & Basil Soup with Harissa

The secret to a memorable tomato soup isn’t simmering a pot on the stove for hours — it is dry oven heat. Dutch greenhouse tomatoes are often watery and muted outside peak summer. If you boil them straight in stock, you end up with a pale, acidic soup that tastes like hot tomato juice. Roasting halved tomatoes on a sheet pan at 200°C (400°F) for 35 to 40 minutes drives off excess water and caramelizes their natural sugars along the cut edges.

Pairing those blistered, sweet tomatoes with North African harissa paste bloomed briefly in olive oil gives the soup a smoky, spiced depth and a velvety body without needing a drop of heavy cream.

What to Know Before Cooking in the Netherlands

• Choosing the right tomatoes: Pick Roma (plum) tomatoes or ripe vine tomatoes (trostomaten). Roma tomatoes have denser flesh, fewer watery seed pockets, and higher pectin, which helps the soup emulsify into a thick, creamy texture when blended.
• Buying harissa in Dutch supermarkets: Turkish and Moroccan grocers stock classic tins of Le Phare du Cap Bon (which packs serious chili heat — start with 1 tablespoon if using the tube or tin). Standard Dutch supermarkets like Albert Heijn and Jumbo carry milder glass jars of harissa or rose harissa (brands like Souq or Al’Fez) with toasted caraway, coriander seed, and roasted red pepper (see our complete harissa substitute guide for tube-vs-jar ratios and swaps). Pair a bowl of this soup with our Crispy Air Fryer Chickpeas or Crispy Air Fryer Halloumi as crunchy toppers, or alongside warm flatbread and Crispy Air Fryer Falafel.
• Use the tender basil stems: Don’t throw away the thin basil stems. Blend half the bunch — stems and leaves together — directly into the hot soup for herbal backbone, and save the prettiest leaves to ribbon on top right before serving.

Instructions

1. Sheet-Pan Roasting (35–40 minutes)

Preheat your oven to 200°C (400°F) convection / fan or 220°C (425°F) conventional. Halve 1.2 kg of tomatoes lengthwise and arrange them cut-side up on a large baking sheet. Tuck the onion wedges between the tomatoes. Slice the top 0.5 cm off the whole head of garlic to expose the cloves, drizzle with a teaspoon of olive oil, and wrap the bulb loosely in aluminum foil. Place the garlic packet on the tray and drizzle the tomatoes and onions with 1.5 tablespoons of olive oil, a generous pinch of sea salt, and freshly cracked black pepper. Roast for 35 to 40 minutes until the tomatoes are collapsed and darkly blistered around the edges.

2. Blooming the Harissa (2 minutes)

Set a heavy-bottomed soup pot or Dutch oven over medium-low heat with 1.5 tablespoons of olive oil. Add the 1.5 tablespoons of harissa paste and stir continuously for 1.5 to 2 minutes. The oil will turn brick-red and release aromas of toasted cumin, garlic, and roasted chili. Blooming the paste in fat unlocks its fat-soluble aromatics and rounds out any raw edge.

3. Combining & Deglazing the Tray

Remove the baking sheet from the oven and let the garlic packet cool for 2 minutes until safe to handle. Squeeze the jammy, roasted garlic cloves out of their papery skins directly into the pot with the harissa oil and mash them briefly with a wooden spoon. Tip the roasted tomatoes, onions, and all accumulated tray juices into the pot. Pour a splash of the hot vegetable stock onto the warm baking sheet, scrape up the caramelized brown fond with a spatula, and pour every drop into the pot.

4. Simmering and Blending Smooth

Add the remaining hot vegetable stock (600 ml total) and bring to a gentle simmer for 10 minutes so the natural pectin from the tomatoes and the starch from the roasted garlic meld with the broth. Remove the pot from the heat, toss in half of the fresh basil (stems included), and blend with an immersion blender for 1 to 2 minutes until completely velvety. Taste and adjust: if winter tomatoes leave a sharp acidic edge, balance it with ½ teaspoon of sugar or an extra swirl of olive oil.

5. Serving

Ladle the piping-hot soup into warmed bowls. Top with the remaining basil leaves sliced into thin ribbons, cracked black pepper, and a generous drizzle of extra virgin olive oil. Serve with crusty toasted sourdough or as a starter before a warming bowl of Quick Red Lentil Dahl.

Troubleshooting

• Soup turns out too thin: If the roasting tray was overcrowded, the tomatoes steamed instead of evaporating their water. Simmer the blended soup uncovered for an extra 5 to 8 minutes to reduce and concentrate it.
• Harissa tastes bitter: If the heat in Step 2 is too high, the sugars and dried chilies in harissa scorch quickly. Keep the burner on medium-low so the paste sizzles gently rather than smoking.
• Garlic cloves dried out: Never roast an exposed head of garlic unwrapped for 40 minutes at 200°C — the cut tips turn hard and acrid. Wrapping the oiled bulb in foil steams and roasts the cloves simultaneously into a soft paste.

Storage and Reheating

• Fridge: Store cooled soup in an airtight container in the refrigerator for up to 4 days. The roasted garlic and harissa meld even deeper overnight.
• Freezer: Because this soup is emulsified with olive oil and roasted garlic rather than dairy cream, it freezes cleanly without splitting for up to 3 months. Reheat gently on the stovetop and add fresh basil just before serving.