Rinse canned black olives, pat dry with a kitchen towel, and chop finely.

Cream softened butter in a bowl, then add sifted flour, Parmesan cheese, black pepper, and rosemary. Mix until partially combined.

Add chopped black olives and mix lightly. Gradually add milk until the dough comes together into a single lump.

Shape the dough into a cylindrical log, wrap in parchment paper, and freeze for 1-2 hours.