I imagine one could use other roots here as well, individually or in combination. It is something of a myth that risotto must be constantly stirred. One must pay attention to the dish, but frequent stirring is usually enough–and one can prepare other parts of the meal in between stirrings (or not). You will probably not use up all of the broth.
3 c peeled, small diced celeriac
1 1/2 c chopped onion
3 T butter
1 c arborio or medium-grain white rice
1/2 c dry white wine, optional
5 c chicken or vegetable broth
1 1/2 c grated Parmesan or Romano cheese, divided
salt and pepper, to taste
1. Melt butter in a large skillet over medium-low heat. Stir in celeriac cubes and onion. Cover and cook, stirring often, until the celeriac is tender but not brown, about 10 minutes, depending on the size of the celeriac dice. If the celeriac is browning, turn down the heat some.
2. Meanwhile, heat the broth in a saucepan to a bare simmer. Keep warm.
3. Once the celeriac is tender, mix in the rice, stirring constantly for a minute or two. Pour in the wine, turn up the heat to medium, and stir the mixture until the wine has almost evaporated. Add a cup of the warm broth and stir until the broth has almost been absorbed by the rice. Keep adding broth, in one-half cup increments, stirring occasionally, until each addition of stock is nearly absorbed. Once rice is al dente–tender, with a soft crunch in the center, about, 18 or so minutes (you’ll know, because the broth will start taking longer to be absorbed, meaning the rice is becoming tender)–mix in about half the grated cheese, stirring to combine. Add some salt and pepper to taste, remembering that both Parmesan and Romano are somewhat salty, and taste for seasoning. Serve, sprinkling additional cheese on each portion.