Soak the red chilies in water for about two hours. Drain and then toast on a hot, dry skillet until they start to darken. Add the garlic, cumin and coriander and toast until the seeds turn a couple of shades darker. Remove everything to a blender or food processor along with the vegetable stock and process into a fairly smooth paste. Set aside.
Put the liner in the Instant Pot and set to saute. Add ¼ cup of vegetable stock and when it is hot, add the onions, garlic and ginger with some salt. Saute until the onions soften. Add a quarter cup more of water if they start to stick.
Add the chickpeas, carrots, potatoes, tomatoes, coriander and cumin powders, thyme and turmeric into the Instant Pot. Stir to mix and add 2 cups of vegetable stock. Add salt to taste and mix it in.
Place the lid on the Instant Pot and set to pressure cook at high for 10 minutes. After cooking is done, wait 10 minutes and release the pressure manually.
Put the IP back on saute and stir in 2 tbsp of harissa. Bring to a boil, and turn it off. (Store remaining harissa in the freezer in an airtight container for future use).
Serve the chickpea stew hot over rice with wedges of lemon, spring onions and cherry tomatoes for a healthy, vibrant meal.