For the rosemary cantuccini, pluck the rosemary needles from the branches and chop finely. Peel the garlic clove and chop very finely.
Put all the ingredients – except for one egg yolk – in a large bowl and work into a smooth, supple dough.
Sprinkle the work surface with flour. With floured hands, form long rolls from the dough. Line a baking sheet with parchment paper and place the rolls on it, spacing them apart. Whisk the egg yolk and brush the cantuccini with it. Bake in the preheated oven at 180 °C for about 20 minutes.
Take the cantuccini out of the oven and cut into slightly thicker slices at an angle. Place in the oven again and bake at 150 °C for another 20 minutes.
Remove from the oven, let cool and put into tins.