Peel the beetroot, onion and garlic and cut into fine cubes. Warning: beetroot has a very strong color; so it makes sense to wear gloves when peeling!
Heat olive oil in a large saucepan and briefly sauté the cut vegetables. Add the risotto rice and continue to sweat until the rice grains are translucent. Add the red wine and let it boil down. Gradually add the broth, stirring constantly. Let it boil down again and again before adding new stock to the pot. You may need a little more broth until the rice is done and gets the desired creamy consistency.
Finally stir in the butter, grated Parmesan and horseradish and season with salt and pepper. Serve immediately.