Cook the rice according to package directions. Use vegetable broth instead of water for a more intense flavor.
Line a baking tray with some parchment paper. Slice the mushrooms, place them onto the baking tray and bake them for about 15 or 20 minutes or until golden brown.
Cook the cauliflower and the milk in a saucepan or a skillet until the cauliflower is soft (5-7 minutes).
Place the cauliflower and the milk in a blender with the rest of the sauce ingredients (lemon juice, garlic powder, onion powder, nutritional yeast and salt) and blend until smooth.
Mix the sauce with the rice in a skillet and cook for about 2 minutes.
Serve with the baked mushrooms and some chopped parsley on top.