Recipe:

1. Prepare for fermentation by cleaning your surface and utensils. Sterilise your up-cycled glass containers (old jam jars work well) by pouring boiling water into them. Empty the water out and leave them to dry. Top tip: it's important to keep everything clean while you're making this recipe (including your hands) to stop any bacteria disrupting the fermentation process.
2. Wash the kale well, and slice with the stem on. Don't worry, the stems will soften as they ferment. Using carrot and spring onions? Scrub them clean and grate the carrot, then finely chop the spring onions.
3. Put the kale in a large mixing bowl with the grated carrot and spring onions (if you're using them). Sprinkle with salt, toss everything together, press down and let rest for 2 hours. This helps soften the veg and lets them release most of their liquid.
4. Blitz the spicy tomato relish, garlic, ginger (no need to peel it), soy sauce, coconut sugar, and water in a food processor. Blend until smooth.
5. Rinse the veg to remove excess salt, then leave to drain in a colander over the sink for a minute before putting it in a clean mixing bowl.
6. Pour the kimchi sauce over the veg, and mix well to coat. Massage it into the veg using your hands.
7. Transfer the kale mix to your sterilised jars and press down. If you need more liquid to cover the vegetables, add a little water. Seal the jar and leave it to ferment somewhere cool for 2-3 days for a mild taste, or for a few weeks for a stronger taste.
8. Open the lid every couple of days, to release excess gases and press the vegetables down into the liquid with a spoon. A good sign of proper fermentation is seeing little bubbles in the sauce when you press down.  After a couple of days of fermenting at room temperature, you can transfer the jar to the fridge, where it'll last for a couple of weeks.