Add the cashews to a bowl and cover with boiling water.
Peel and chop the onion into large chunks, peel the garlic, and cut the tomatoes in half and then half again and add to a baking tray lined with parchment paper.
Drizzle with 2 tbsp of olive oil and a few cracks of black pepper and toss to make sure everything is well coated.
Bake for 30 minutes.
During the final 10 minutes, bring a large pot of water to a boil and cook pasta according to package instructions.
Let cool for a few minutes until the tomatoes are easy enough to handle. Carefully remove the skins of the tomatoes. They will be hot, but the skins should peel off very easily. I like to hold the tomatoes right over the blender and pinch the back of the skins so the inside falls right inside.
Drain and rinse the soaked cashews and add to a blender.
Add the roasted tomatoes, onion and garlic to a blender and be sure to get all the juices in there.
Add all remaining ingredients but only 1/4 cup worth of basil to a high speed blender and process until completely smooth.
Taste and adjust seasonings as desired.
Pour the sauce over the cooked pasta and stir until well coated.
Add in the chopped basil and mix through. Garnish with fresh pepper, red pepper flakes and extra basil if desired and enjoy!
For the tomato sauce, you will want to use just plain tomato sauce from a can. The sauce shouldn't need any additional liquid because the tomatoes release a lot of juice. If the sauce is too thick, you can add a few tbsp of vegetable broth, water, or even almond milk. Once prepared, this recipe will store in the fridge for 5 days. To reheat it, I suggest adding to a pan on the stove with a splash of water, broth, or milk to make sure it gets nice and creamy again.Yellow onion will yield the best flavor, but white or red onion will also work. Red onion will have a stronger flavor, but will still be delicious!