Cook the pasta according to the package instructions. While the pasta is cooking, preheat the oven to 375ºF. Once the pasta is cooked, drain it and set it aside.

Put the water, cashews, pumpkin, nutritional yeast, and miso in a high powered blender. Blend on high until smooth and creamy. Transfer the sauce into a saucepan on the stove and whisk in the brown rice flour. Turn on the stove to medium heat and continue to whisk until the sauce has started to thicken slightly, about 1 minute. Stir in the pasta and shredded cheese.

Pour into a square baking dish and sprinkle with breadcrumbs. Bake on the center rack for 20-25 minutes until the top has started to brown and the mixture is bubbling. Remove from the oven and serve immediately.