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Howth Castle Cookery School

Roasted Pumpkin & Sweet Potato Soup with Dried Herb and Seed Crumbs Recipe

If you think pumpkin soup is a bit predictable, this one might change your mind.

Velvety, sweet and deeply savoury, it’s everything you want from a bowl of soup once the evenings turn cold, with a crunchy, cheesy topping that makes it feel like a proper meal.

The secret is roasting. Instead of simmering everything in a pot, the pumpkin, sweet potato, onion, celery and a whole head of garlic go into the oven together, where they soften, caramelise and take on a rich, mellow sweetness. The garlic softens, the thyme tucked inside the pumpkin gently perfumes the flesh, and a quick blitz brings it all together into something silky and smooth.

Then there’s the crumb. Butter, flour, parmesan, dried herbs and pumpkin seeds bake into a golden, crunchy topping that sits somewhere between a crumble and a crouton. It adds a lovely contrast to the smooth soup, and it means the pumpkin seeds don’t go to waste.

This is our Howth Castle Cookery School version, and it’s ideal for a weekend lunch, a Halloween supper or a batch to see you through the week. The oven does most of the work, and the soup freezes well (just keep the crumbs separate). If you love cooking with the seasons, sign up for our newsletter, and we’ll let you know when our next classes are on.

Let the crumbs cool completely on the tray before you break them up. They keep crisping as they cool, so don’t worry if they feel a little soft straight out of the oven.

Make a big pot, and don’t be surprised if everyone comes back for a second bowl.

Ingredients Method
  • Kabocha pumpkin (about 1.5kg)
  • 1 sweet potato (about 400g)
  • 1 head of garlic
    Extra virgin olive oil
  • 2 onions
  • 1 celery stick
  • 1 thyme sprig
  • Salt & pepper
  • 500ml vegetable stock

For the crumble

  • 45g butter
  • 50g plain flour
  • 40g grated parmesan
  • Handful of pumpkin seeds
  • 1 tsp dried herbs
  1. Preheat the oven to 180°C.
  2. Cut the pumpkin in half vertically and scoop out the seeds. Don't throw them away: rinse off the pulp, pat them dry and set them aside for the crumbs.
  3. Peel the onions and cut them in half.
  4. Cut the sweet potato in half lengthways.
  5. Roughly chop the celery.
  6. Line a baking tray with parchment paper. Place the pumpkin halves face down with the thyme hidden inside, then add the onion, sweet potato, celery, and garlic.
  7. Rub the butter into the flour with your fingertips until it looks like coarse breadcrumbs. Stir in the parmesan, salt, dried herbs and pumpkin seeds. Spread the mixture over a second lined baking tray in an even layer.
  8. Put the vegetables in the oven for 50 minutes, or until the pumpkin is completely soft and a knife slides in easily. Add the crumb tray for the last 15 to 20 minutes, until golden and crisp. Leave it to cool on the tray, where it will crisp up further.
  9. Leave the vegetables to cool for a few minutes. Squeeze the soft garlic out of its skins and discard the thyme stalk. Scoop the pumpkin flesh away from the skin and transfer it to a large pot with the roasted onion, sweet potato, celery, garlic and thyme leaves. Add hot stock and blend with a hand blender until smooth. Add more stock until you reach the consistency you like.
  10. Warm the soup gently over a low heat, then taste and adjust the seasoning with salt and pepper.
  11. Ladle into warm bowls, scatter the crumb over the top and finish with a drizzle of good olive oil.

Posted on 14 Oct 2026.