Preheat the oven to 350°F (180°C).
Line a baking sheet with parchment paper.
Mix the flour, baking powder, and salt together and set aside.
Beat the butter and sugar together until light and fluffy. Beat in the eggs, one at a time.
Stir in the flour mixture and rosemary to form a soft dough.
Form the dough into sausage shapes about 2 inches (5 cm) in diameter. Place them on the baking sheet and bake for about 25 minutes, until they are lightly colored and fairly firm to the touch.
Remove them from the oven and allow them to cool. When the rolls have cooled, cut them on an angle into slices ¾ inch (2 cm) thick.
Stand the slices on edge about ½ inch (1.3 cm) apart on the baking sheet. Use a second baking sheet if necessary.
Return them to the 350°F (180°C) oven for another 20 minutes, until they have become a bit darker and firmer.
Allow them to cool completely, then store them in airtight containers.