Prep by chopping all your veggies. Grease a casserole dish with some olive oil.
Preheat oven to 350 degrees.
Warm a large soup pot over high heat. Add in the olive oil and vegan butter.
Add the onions, green beans and mushrooms to the soup pot. Saute on high for 2-3 minutes, stirring every thirty seconds or so. Add the fresh sprigs of thyme over top - crush a few leaves right into the mix too. then place lid on pot. Reduce heat to medium and cook for another 2-3 minutes to soften the veggies and combine the flavors.
While the veggies are cooking, add the broth, cashews, salt and pepper to a blender. Blend from low to high until silky smooth. No lumps!
Reduce the stove heat to low, lift lid off of the pot and pour in the cashew cream. Fold everything together and cover with lid. Let this mixture cook for another two minutes.
Turn off the heat and remove lid of soup pot. Pour the mixture into a lightly greased casserole dish. Smooth everything out so it is even. Top with the cheese followed by the crispy onions.
Cover dish with foil and bake at 350 degrees for twenty minutes.
Remove the foil and broil for 2-3 minutes to brown the onions. (don't burn the onions! I slightly did my first time making this.)
Let casserole cool for ten minutes before serving! Delicious as leftovers.