Heat the butter and half the olive oil in a large frying pan over a medium-high heat. Add the mushrooms and cook on one side, pressing down, until really crispy. Turn over, add the garlic and cook the other side, again until golden. You may need to do this in batches if you don't have a big enough pan. Add the paprika, season well with salt and pepper and set aside in a bowl.
Heat the remaining oil in the pan, add the kale and fry for 3 to 4 minutes until softened. Season with lots of black pepper and toss with the mushrooms.
Heat the grains according to the packet instructions and mix with the extra-virgin olive oil, herbs and lemon juice to taste. Divide the grains between four bowls and add the mushrooms and kale. Top each bowl with a dollop of sour cream and a sprinkle of smoked paprika and serve.