In the pitcher of a high speed blender, combine the cashews and ¾ cup of boiling water. Set aside for 20 minutes so the cashews soften.
½ Cup Raw Unsalted Cashews, ¾ Cup Boiling Water
Bring a large pot of water to a boil. Salt it well and cook the pasta according to package directions. When you drain the pasta, reserve about ½ cup of the cooking liquid.
1 Pound Pasta of Choice
Meanwhile, heat a large skillet over medium heat. Add the oil onions and bell pepper as well as ½ teaspoon of salt and a few cracks of black pepper and cook, stirring occasionally, until the vegetables are soft and have barely started to brown, about 10 minutes. Then, add the garlic and cook until fragrant, about 1 minute.
2 tablespoon Extra Virgin Olive Oil, 1 Medium Yellow Onion, ½ inch dice, 2 Medium Red Bell Peppers, ½ inch dice, 4 Large Cloves of Garlic, minced, Salt and Black Pepper
Use the spoon to push the vegetables to the sides of the pan and add the tomato paste into the center. Cook, stirring frequently for about 3 minutes. This gives the tomato paste more depth of flavor.
¼ Cup Tomato Paste
Turn the heat off and add the harissa and lemon juice. Use the wooden spoon to scrape the brown bits from the bottom of the pan.
½ Cup Harissa Sauce, 1 tablespoon Lemon Juice
Do not drain the water from the cashews! Add the pepper and harissa mixture into the blender with the cashews and their water. Blend on high until completely smooth. Taste the sauce and add any additional salt and pepper you desire, here. Then, pour the sauce back into the pan.
Add the cooked pasta into the pan and gently sir it all together. Serve.