How to Make It
In a large, heavy saucepan, toast the poppy seeds over high heat, stirring, until they smell slightly nutty, about 2 minutes. Transfer to a small bowl. Add 5 tablespoons of the butter to the saucepan and cook over moderate heat until beginning to brown, about 5 minutes. Stir in the beets and season with salt and pepper. Reduce the heat to low, cover and cook until the beets are tender, about 10 minutes.
Meanwhile, in a large pot of boiling salted water, cook the fettuccine until al dente. Drain and transfer to a large warmed serving bowl. Toss the fettuccine with the remaining 1 tablespoon of butter and the grated cheese; season the pasta with salt and pepper. Stir in the beets and sprinkle the pasta with the toasted poppy seeds. Add the balsamic vinegar to the fettuccine, garnish with chives, season again with salt and pepper and serve.