Place your cashews in a small heatproof bowl and cover them with boiling water. Set them aside to soak for 20 minutes, then drain.
In the meantime, steam your cauliflower, potato and carrot separately over a saucepan filled with steaming water, until softened. Set the cauliflower florets aside.
Place the potato and carrot in a blender or food processor. Add the white miso paste, plant milk, oats, salt, black pepper, paprika, nutritional yeast, lemon juice, coconut oil, and the drained cashews. Blend on high for 3 to 4 minutes, until you get a smooth sauce.
Combine the cauliflower and sauce in a bowl. Transfer the mixture to a greased, ovenproof dish, then preheat your oven to 390°F (200°C).
Heat the olive oil in a large, nonstick skillet over medium heat. Fry the red onions for 3 to 5minutes, until translucent. Add the brown sugar and cook for 8 to 10 minutes, stirring frequently, until the onions caramelize.
Top the cauliflower bake with the caramelized onions and almond flakes. Place the ovenproof dish into the oven and bake for 8 to 10 minutes, or until the top turns golden. Serve hot alongside roast potatoes and your favorite roast.