Preheat the oven to 375ºF/190°C and grease a 9x13 baking dish with vegan butter or cooking spray.
Place cashews in a small bowl with 1 cup of boiling water and soak for 15 minutes.
In a large pan, heat 2 tablespoons of olive oil over medium heat. Add chopped onion and sauté until soft and translucent, about 3-4 minutes. Stir often.
Add minced garlic, rice, and Italian seasoning. Cook, stirring, for 1 minute.
Add vegetable broth, salt, black pepper and garlic powder. Stir and cover the pan with a lid. Bring to a simmer (essentially to a heat just below boiling until small bubbles form around the edges) and then turn the heat to low (so the liquid is still moving). Cook for 5 minutes.
Add broccoli florets. Stir and cook covered with a lid for 5 more minutes.
While rice and broccoli are cooking, place soaked cashews into a blender along with the water they were in. Blend until smooth, about 2 minutes.
Remove the pan from heat. Add blended cashew cream and 1 cup grated vegan cheddar, then mix until combined. Taste and add more salt and pepper if needed.
In a medium bowl, mix the melted vegan butter, panko breadcrumbs, paprika and dried thyme.
Transfer the rice and broccoli mixture to the prepared baking pan. Sprinkle with the remaining cheese and panko breadcrumbs.
Bake until bubbly and golden on top, about 10 minutes. Remove from oven, let cool slightly, then serve and enjoy!
Notes
To store: Store leftover broccoli cheese rice casserole in an airtight container in the refrigerator for up to 4 days. To reheat, simply cover it and place it in the oven at 350ºF until warmed through or heat individual servings in the microwave.To freeze: This cheesy broccoli rice casserole can be frozen for up to 2 months. Wrap it tightly in the baking dish or place leftovers in an airtight container.