Chop all the veggies(onion, bell peppers, and zucchini) and set aside.
Drain the water from the black beans and rinse it and set it aside.
Mix 3 oz of the tomato paste with 1 cup of water and set aside. Make sure there aren't any lumps.
How to make vegetarian zucchini chili in Instant Pot
Set the Instant Pot in saute mode. Add the 3 tbsp of oil and after 30 to 45 seconds, when the oil is hot, add the chopped onion, garlic, and ginger (optional). Saute until the onion turns soft and tender or for about 4 to 5minutes.
When it starts to turn brown, turn off the Instant Pot. Turning it off after sauteing onion helps to prevent the burn signal in the newer Instant Pot models.
Now add the corn, zucchini, bell peppers, and all the spices - dark chili powder, smoked paprika, ground cumin, ground coriander, cocoa powder, and brown sugar. Gently mix.
Add the tomato paste mixed with water and mix again.
Now add the drained beans and gently spread it—no need to mix. As the canned beans were already soft, I did not mix them frequently. Add the remaining ½ cup of water.
Close the Instant Pot. Make sure the vent is in the sealing position. Select manual/pressure cook and set the time to 3-minutes at high-pressure mode. When the cooking is complete, wait for 5 minutes, then quickly release the remaining pressure. Carefully open the lid after releasing the pressure and mix the chili.
As you can see, the zucchini is soft but not mushy.
Now add the chopped cilantro and mix well. Add cheese, if using, and serve warm.
I used my homegrown zucchinis, and they weren't tender by the time I plucked them. So I went ahead with 3 minutes of cooking time. If you are using soft and tender zucchini, 2 minutes of cooking time should be enough.
Instead of 2 cans of black beans, you can use 1 can of black beans and 1 can of red kidney beans.
Sugar is optional. Adjust the salt and spices as per your preference. Make sure you use unsweetened cocoa powder. If you don't have unsweetened cocoa, you can skip it.
Instead of zucchini, you can use butternut squash or sweet potatoes. Or instead of zucchini, you can add one more can of beans. You can add black bean, kidney beans, and navy beans and make it like a three-bean chili.