Preheat the oven to 400 degrees. Toss peppers, onion and garlic with 1 tablespoon olive oil. Spread evenly on a baking sheet, sprinkle with salt and roast until the onion is soft and translucent, about 20-25 minutes, stirring once halfway through.

While the vegetables are roasting, boil the pasta until al dente in a pot of salted water. Drain the pasta and reserve 1/2 cup of the pasta cooking water. Set aside.

Add 1 tablespoon olive oil to a skillet over medium heat. Add the broccoli and yellow peppers and cook until they are fork tender, about 5-7 minutes. You can add a small splash or two of water to the skillet to help the cooking along. Season vegetables with salt and pepper and remove from heat.

When the vegetables are done roasting, remove them from the oven and let cool slightly, then peel peppers and remove the seeds.

Add peppers, onion and garlic to a high speed blender. Drain the soaked cashews and add to blender along with 1 tablespoon olive oil, basil, nutritional yeast, 1/2 teaspoon sea salt. Blend until smooth and creamy, adding reserved pasta water one tablespoon at a time to thin the texture (I used 5 tablespoons) and scraping down the sides of the blender a few times. Blending can take about 1-2 minutes to get the sauce to a velvety smooth consistency.