Cook the pasta just to al dente according to package directions.
Meanwhile, heat a large, nonstick skillet on medium-high heat. Add the butter, onion, and garlic. Saute until barely golden and fragrant. Add the flour and cook briefly. Add the vegetable stock and cook a minute to scrape up any bits from the pan with a wooden spoon or silicone spatula. Remove from the heat and set aside.
In a food processor, add the cashews. Process until broken down and starting to get creamy. Add the Dijon, lemon juice, salt, pepper, and almond milk, and process until very smooth, scraping down the sides of the bowl as necessary. Add the onion-veggie stock mixture, and process again until very smooth.
Drain the macaroni and put back in the pot. Add the RO*TEL to the cashew cream sauce and stir. Add the RO*TEL mixture to the pasta and transfer all to a 13x9 bake dish.
Combine the panko breadcrumbs and olive oil. Top the casserole with the panko mixture. Bake at 350F for 20-25 minutes until nice and hot. Yields: 6 servings as a main course; 8 servings as a side.