Peel and chop the onion and garlic.
Add olive oil to a pan that is set on a stove set to medium-high heat. Add the chopped onion and garlic to the pan and sauté for about 8 minutes. Stir often so this mixture does not burn.
While the onion and garlic sauté, chop the jalapeño. You can include the jalapeño seeds if you prefer it spicy, or cut them out.
Once the onions and garlic have been sautéing for about 8 minutes, add in the chopped jalapeño and sauté for 2 more minutes, stirring often. Then, turn the stove down to medium heat.
Add the frozen spinach to the pan and let it sauté for about 4-5 minutes. The excess water from the thawing frozen spinach will evaporate and not dilute this recipe.
Turn the stove to low heat at this point. Then add in the harissa and coconut milk and stir well until all ingredients are incorporated.
Then, turn the stove off. Season this with salt and black pepper and serve it as is.
Or, add this mixture to a blender and blend it until it is smooth. If you have an immersion blender, use it to blend this so it is as smooth or chunky as you prefer.