Recipe by Yotam Ottolenghi: Vegetarian Delicacies Penguin Random House, 2014.
Heat the butter with the olive oil.
Sauté chopped onions over medium heat until soft and slightly caramelised.
Add the garlic, lemon slices, thyme, and sauté for 2 minutes.
Add the rice and the finely sliced Brussels sprouts.
Stir-fry for 1 minute, then deglaze with the white wine and simmer for 1 minute.
Gradually add the vegetable stock, salt and pepper. Keep stirring and adding vegetable stock until the rice is cooked slightly al dente and the stock has been used up.
In the meantime, heat the sunflower oil in a large pot. Once the oil is very hot, gradually fry the quartered Brussels sprouts (for about 1 minute). Then drain on a plate lined with kitchen paper and keep warm until the rest of the cauliflower is fried.
Dab off the excess fat.
Gently fold the Parmesan and blue cheese into the risotto with the tarragon and half of the fried quartered Brussels sprouts.
Spread the remaining Brussels sprout quarters on top. Sprinkle with the grated lemon zest and drizzle with lemon juice.