1/4cupbreadcrumbs (optional; you can make your own by pulsing two slices of toasted whole grain bread in a food processor, or you can use a gluten free brand)
For the cheesy sauce:
1/2cupraw cashews, soaked for at least 2 hours and drained(70g before soaking)
Preheat your oven to 350°F. Fill a medium sized pot with water and fit with a steamer attachment. Bring the water to a boil and steam the broccoli florets until crisp-tender (about 3-4 minutes). Remove them from heat.
Blend all of the sauce ingredients together in a high speed blender or a food processor until they're totally smooth.
Heat the olive oil in a large skillet over medium heat. Add the onions and celery, and sauté the vegetables until the onion is clear and soft (about 7 minutes). Add the quinoa and the broccoli to the skillet. Add the sauce and stir everything to heat it through.
Transfer all ingredients to an oiled 7x11 or 8x12 baking dish. Top with breadcrumbs, if using. Bake for 30-35 minutes, or until the casserole is bubbling gently and the breadcrumbs are golden. Allow to cool for 15-20 minutes before cutting into squares and serving.