The raw cashews need to be soaked for at least 8 hours, I like to soak them overnight. If you forgot and are in a pinch, you can soak them in boiling water for 20-30 minutes.
Once you are ready to make the pasta, begin boiling water for the pasta and cook according to package directions.
While the pasta water is boiling and the pasta is cooking, make the sauce. In a medium non stick, heat the olive oil on medium high. Then add the sliced onion and chopped garlic.
Saute, reducing heat as needed for about 5 minutes or until the onions are cooked and beginning to caramelize.
Next, add the roasted red peppers to the skillet and saute for another 2-3 minutes to heat everything together. Remove from heat.
Then, drain the cashews and add them to a blender.
Now, add the onions, garlic and peppers to the blender. As well as the vegetable broth and a pinch of salt and red pepper. Blend until the sauce is completely smooth, scraping down sides as needed.
Once the pasta is done, add the pasta back to the pot and pour the creamy red pepper sauce over the pasta. Toss to coat and sprinkle with a few more pinches of salt and a pinch of red pepper.
Now add the olives, artichokes and radicchio to the pot and toss to coat. The heat from the pasta should heat everything, but you can turn the pot on low and toss to heat everything if you need to.
Taste and adjust seasoning. Serve immediately. I like to top mine with fresh parsley and vegan Parmesan.