Peel the sweet potato and slice into quarters. Peel the shallots and slice in half. Leave the garlic in it's paper, and place the sweet potato and shallot pieces on a foil lined baking sheet. Toss it all with a drizzle of olive oil, salt and pepper. Roast, removing the garlic after the first 15 minutes. Roast until the sweet potatoes are tender and the shallots are browning around the edges, about 30 minutes. Remove from the oven and set aside to cool slightly.
Meanwhile, cook your pasta until al dente, reserving some of the starchy pasta water.
Drain your cashews and place them into a high speed blender with the sweet potato, shallots, (peeled) garlic, olive oil, balsamic, tomato paste, rosemary, and a few pinches of salt and pepper. Puree, adding water as needed to get the blade moving. Taste and adjust seasonings.
In a large skillet (or a bowl) toss the cooked pasta with some of the sauce. Add pasta water as needed to loosen, and add more sauce to your liking Add chopped chives, toasted pine nuts and a pinch of red pepper flakes. Taste and adjust seasonings and serve.
Feel free to toss in more veggies... steamed spinach, kale or roasted broccoli would be all be delicious additions.
Make ahead tip: store finished sauce in the fridge for up to 3 days. When you're ready to serve, boil pasta and toss it all together.
For the smoothest sauce, a vitamix-like high powered blender is recommended. In a pinch, I can get away with soaking my cashews only 30 minutes.
Recipe by Love and Lemons at https://www.loveandlemons.com/sweet-potato-vegan-alfredo/