Bring a pot of water to a boil for the pasta. In a container suitable for an immersion blender, add the washed, dried, and chopped dill, hazelnuts, cheese, a pinch of salt, and a pinch of pepper.

Start blending in short bursts to prevent the blades from heating up, while slowly drizzling in the extra virgin olive oil. The pesto will have a thick texture.

When the water boils, add salt and cook the pasta. Once the pasta is cooked, drain it, making sure to save some of the cooking water.

Toss the pasta with the pesto off the heat, adding one or two tablespoons of the reserved cooking water to slightly thin the sauce and help it coat the pasta.