Chop the walnut halves as desired (from coarsely chopped to finely ground) and stir into the softened butter with salt and pepper. Serve with bread, pasta and vegetables.
Tip:
The walnut halves can also be caramelized with a little sugar in a non-stick pan before they - well cooled - are crushed and stirred into the butter.
You can replace the walnut kernels with ground hazelnuts or pistachios.