Prepare rice in boiling salted water according to package instructions, drain and allow to cool. Peel onions and garlic and dice finely. Heat 2 tablespoons of oil. Steam onions, garlic and thyme for about 10 minutes. Let cool off. Clean and finely chop the mushrooms and fry them in 2 portions in 2 tbsp. oil, season with salt and continue to fry until the liquid has evaporated. Leave to cool
Chop or grind cashew kernels very finely in the universal chopper. Coarsely chop the walnut kernels. Grate cheese. Whisk eggs in a large bowl. Add rice, parmesan, nuts, crème fraîche, onion-garlic and mushroom mixture and knead. Season with salt, pepper, coriander and paprika powder
Grease a box mould (11 x 30 cm) and sprinkle with breadcrumbs. Pour in rice mixture and smooth it down. Cook in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for 50-60 minutes
Place the roast in the pan on a cake rack, after approx. 10 minutes carefully turn out of the pan. Serve roast hot or cold with salad