Add pasta to a large pot of boiling, well-salted water and cook according to package instructions. Drain and cover to prevent drying.
Meanwhile, heat a large skillet over medium heat. Once hot, add olive oil and garlic, stirring quickly to ensure it doesn’t burn.
Next, reduce heat slightly and add arrowroot or flour and whisk to combine. Cook for about a minute and then add almond milk 1/4 cup at a time (as original recipe is written, 1 3/4 cups total, working up to 2 cups later on if needed // adjust if altering batch size) and whisk to prevent clumps. Cook for 2 minutes.
Transfer to a blender and add salt, pepper, vegan parmesan cheese, nutritional yeast, garlic powder, and blend on high until creamy and smooth, scraping down sides as needed. Taste and adjust seasonings as needed - you want it to be pretty cheesy and salty so don't be shy.
Return sauce back to skillet and cook on medium heat until it bubbles, then reduce heat to low and cook until thickened, stirring frequently.
If sauce is too thick, add a little more milk. If too thin, scoop out some sauce in a 1/2 cup measuring cup and whisk in 1-2 tsp more arrowroot or flour (amounts as original recipe is written // adjust if altering batch size). Whisk to combine and add back to sauce. Repeat as needed until desired consistency is reached.
Once sauce is ready, add pasta, peas and toss. Cook for 1-2 minutes to warm through, and then serve with additional vegan parmesan cheese and red pepper flakes.
Leftovers keep covered in the refrigerator for up to a few days, though best when fresh.
*Nutrition information is a rough estimate calculated with Trader Joe's GF Quinoa & Brown Rice Fusili, the lesser amounts where ranges are provided, and without optional ingredients.