Prepare the squash. Heat your oven to 425°F (220°C fan) and line an oven tray with parchment paper. Carefully chop the top (with the end of the stem) off the squash, then cut straight down the middle, so you're left with two long pieces of squash. Scoop the seeds out and place them in a bowl. Slice the tops of the cloves off your garlic heads.

Roast the butternut squash. Drizzle the cut sides of the squash and garlic with a little olive oil, then place the garlic into the cavities where the seeds were. Sprinkle the squash with 1 teaspoon of salt. Turn the squash halves (with the garlic inside) upside down, then place them on your prepared tray. Transfer to the oven for 45 minutes, until super soft and caramelized. When it's ready, you should be able to easily pierce the squash with a knife.

Cook the onions and spices. Set a large saucepan over medium heat, then add 1 tablespoon of olive oil. Add the diced onion and 1 teaspoon of salt, then cook, stirring, for about 5 minutes, until the onion starts to soften. At this point, add the ground cumin, coriander, turmeric, and the chili flakes. Stir the spices through the softened onion for another minute, then remove from the heat until the squash is cooked through.

Make the salted honey seeds. Rinse the squash seeds and remove as much of the squash flesh as you can. Pat dry with a kitchen towel. Place a piece of parchment paper onto a small plate or tray. Set a small pan over low heat, then add the dried seeds. Cook, stirring, for a couple of minutes, until they start to smell nutty and they're developing brown spots. At this point, pour in the honey and add 1 teaspoon of flaky sea salt, then stir them through the seeds for another 30 seconds. Transfer the seeds to the prepared plate to cool and crisp up. PRO TIP: The seeds will get SUPER sticky once they dry, so it's important to use greaseproof paper - they will stick to the plate if you don't.

Add squash, garlic, and stock. Once the squash is super soft (pierce the squash with a knife - it should easily go through the skin into the flesh), remove it from the oven. Scoop the squash from its skin, directly into the pot with the onion and spices. Squeeze the garlic from its skin into the pot too. Pour in the stock, then add the fish sauce and lemon juice. Turn the heat to medium, then stir and bring the soup to a simmer for a couple of minutes, just to let the flavors meld. 

Blitz, season, and serve. You can either use an immersion blender to blitz the soup or transfer it to a stand blender. I prefer using a stand blender for the smoothest consistency, but the immersion blender is easier and creates less washing up, so it's up to you. Blitz the soup until it's super smooth and creamy. If you're using a stand blender, transfer the soup back into the pot, then taste and add more salt if you like. Divide the soup between bowls, then top with a drizzle of chili oil, a scattering of the feta, and the salted honey seeds.