This chilled cucumber soup with Cajun prawns is summer in a bowl. Icy-cold, creamy cucumber soup provides the perfect backdrop for hot, spicy prawns - a temperature and flavor contrast that's absolutely addictive. It's the kind of dish that makes you look like a culinary genius with minimal effort.
The soup itself is no-cook simplicity: just blend cucumbers with tangy buttermilk and fresh mint, then chill. The magic happens when those sizzling Cajun-spiced prawns hit the cold soup at the table.
The Art of Temperature Contrast
Hot-and-cold combinations are a hallmark of modern cuisine, and for good reason - temperature contrast heightens our perception of flavor. The cold soup amplifies the heat of the Cajun spices, while the warm prawns release aromatic compounds that perfume each spoonful.
The key is timing. Cook the prawns just before serving and add them to the soup immediately. If they cool down, you lose that dramatic contrast that makes this dish special.
Why Lebanese Cucumbers?
Lebanese cucumbers (also called Persian cucumbers) are ideal for cold soup:
- Sweeter flavor: Less bitter than regular cucumbers
- Thin skin: No need to peel
- Few seeds: Smoother texture when blended
- Higher water content: More refreshing soup
If you can only find regular cucumbers, peel them and scoop out the seeds before blending. English (seedless) cucumbers work well too.
The Buttermilk Base
Buttermilk provides tang and creaminess without heaviness. Its acidity brightens the cucumber flavor and creates a silky texture. If you don't have buttermilk, make a quick substitute: add 1 tablespoon lemon juice to 1 cup milk and let it sit for 5 minutes to curdle slightly.
For a dairy-free version, blend cucumber with coconut cream thinned with water, or use plain coconut yogurt. The flavor profile will be slightly different but equally delicious.
Butterflying Prawns: Why It Matters
Butterflying the prawns isn't just for presentation - it serves practical purposes:
- More surface area: More space for Cajun seasoning to stick
- Faster, even cooking: The flattened prawns cook quickly and uniformly
- Better heat distribution: Both sides get equally crispy and caramelized
- Elegant presentation: Butterflied prawns look impressive in the bowl
To butterfly: cut along the back of each prawn (through where the vein was), but don't cut all the way through. Open the prawn like a book and press gently to flatten.
Getting Cajun Spicing Right
Cajun seasoning typically includes paprika, garlic powder, onion powder, cayenne, black pepper, oregano, and thyme. The heat level varies by brand - taste before using if you're sensitive to spice.
For homemade Cajun seasoning, combine: 2 tsp paprika, 1 tsp garlic powder, 1 tsp onion powder, 1/2 tsp cayenne, 1/2 tsp black pepper, 1/2 tsp oregano, 1/2 tsp thyme, 1/2 tsp salt.
Perfect for Entertaining
This soup is ideal for dinner parties because:
- The soup base can be made 24 hours ahead
- Prawns cook in just 4 minutes total
- Assembly takes seconds
- The presentation is stunning and impressive
Pre-portion the soup into chilled bowls. Keep them in the refrigerator. Cook the prawns while guests are seated, then add them dramatically at the table for maximum effect.
Chilled Cucumber Soup with Cajun Prawns
Cool, refreshing, with a spicy kick - the ultimate summer soup.
Nutrition per serving
Ingredients
For the Chilled Soup:
For the Cajun Prawns:
Instructions
- Make the soup base. Place chopped cucumber, buttermilk, water, shallots, chopped mint, and salt in a food processor or blender. Process for 2 minutes until completely smooth. Taste and adjust salt and pepper. Transfer to a large jug or container, cover with plastic wrap, and refrigerate for at least 2 hours (or up to 24 hours).
- Butterfly the prawns. Using a small sharp knife, cut a slit lengthways along the centre of the back of each prawn (where you removed the vein), but don't cut all the way through. Open each prawn like a book and press down gently to flatten.
- Season the prawns. Place butterflied prawns in a bowl. Add Cajun seasoning and toss to coat evenly on all surfaces.
- Cook the prawns. Heat a large frying pan or skillet over high heat. Spray generously with olive oil. Add half the prawns in a single layer - don't overcrowd. Cook for 2 minutes on the first side until charred and golden, then flip and cook 2 minutes on the other side until cooked through. Transfer to a plate and cover loosely with foil. Repeat with remaining prawns.
- Serve immediately. Give the chilled soup a stir (it may have separated slightly). Divide between chilled serving bowls. Arrange hot prawns in the centre of each bowl. Scatter with fresh mint leaves and serve immediately while the temperature contrast is at its best.
Recipe Notes
- Make ahead: Soup base keeps refrigerated for up to 24 hours. Cook prawns just before serving.
- Lighter version: Use Greek yogurt thinned with water instead of buttermilk.
- Vegetarian version: Top with grilled halloumi or spiced chickpeas instead of prawns.
- Scale up easily: Recipe doubles or triples perfectly for a dinner party.
- Chill bowls: For best results, chill serving bowls in the freezer for 10 minutes before serving.
Frequently Asked Questions
Why use Lebanese cucumbers for this soup?
Lebanese (Persian) cucumbers are sweeter, have thinner skin, and contain fewer seeds than regular cucumbers. This means a smoother, less bitter soup that doesn't require peeling or seeding. If using English or regular cucumbers, peel them and remove seeds first.
Can I substitute the buttermilk?
Yes, make a buttermilk substitute by mixing 1 cup milk with 1 tablespoon lemon juice - let sit 5 minutes. For dairy-free, use coconut milk thinned with water, or plain dairy-free yogurt. Greek yogurt mixed with water also works well.
How far ahead can I make the soup base?
The cucumber soup base can be made up to 24 hours ahead and refrigerated. In fact, longer chilling allows the flavors to meld better. Give it a stir before serving as it may separate slightly. The soup is best within 24 hours - after that the cucumber can become slightly bitter.
What makes a good homemade Cajun seasoning?
A basic Cajun seasoning combines paprika, garlic powder, onion powder, cayenne pepper, black pepper, oregano, thyme, and salt. For this recipe, store-bought Cajun seasoning works perfectly. Look for brands without MSG if you prefer.
Can I serve this soup as a dinner party starter?
This makes an impressive dinner party starter. Make the soup base the day before. Cook prawns just before serving - they should be hot when they hit the cold soup. The temperature contrast is part of the appeal, so don't let the prawns cool down.
