Soak cashews in hot water for about 1 hour until tender, then drain. Skip this step if using a powerful blender.
Make pumpkin cheese sauce: heat avocado oil in a small saucepan over medium heat. Add onion and garlic and cook while stirring for 3-5 minutes until fragrant and almost translucent, being careful not to burn the garlic. Then add in the vegetable broth and the chopped carrots and cook for another 5 minutes until the carrots are fork tender.
Pour the onion-garlic-carrot mixture into a blender along with the drained cashews and pumpkin puree: blend until smooth, adding a splash of vegetable broth as needed to blend. Add nutritional yeast. Dijon mustard, smoked paprika, salt, and pepper; blend once more and adjust seasoning to taste.
Cook pasta: In a large pot, bring water to a boil and add in dry macaroni. Cook pasta one minute shy from the recommended cook time in the package instructions.
Optional: while waiting for the pasta to cook, make the breadcrumb topping by blending the almonds, garlic powder, onion powder, dried parsley, and salt to a coarse mixture. Do not over blend. Set aside.
When pasta is done cooking, drain and place back into the pot. Pour the blended pumpkin cheese sauce into the same pot and cook until everything is warmed through.
Optional: transfer mac and cheese into a casserole dish, top with breadcrumb topping, and broil for 1-2 minutes while keeping a close eye to prevent burning. Serve immediately.
If you are planning to store this mac and cheese, it is recommended to store the pasta, sauce, and topping separately because the pasta will absorb the sauce and become dry rather quickly. Keep in an airtight container in the refrigerator for up to 5 days.