Sieve the plain flour, salt and baking powder in a bowl. Set aside.
Whisk the egg yolks with the sugar until smooth. Whisk in the butter until well combined. Whisk in the honey and cinnamon.
Stir in the flour mixture gradually to make a smooth dough. Form the dough into a ball and let it rest in a lightly floured bowl at room temperature for at least 1 hour.
Preheat the oven to 180 C / Gas 4. Butter a muffin tin.
Roll out the pastry on a floured work surface to about a 5mm thickness. Cut with a biscuit cutter or small glass into biscuits the same size as your muffin tin. Place the biscuits into the prepared muffin tin.
Bake in the preheated oven until golden, about 15 minutes. Roll out a length of baking parchment onto a work surface. Unmould the biscuits immediately onto the parchment to cool. If you unmould the biscuits quickly, they will be crisp.
The biscuits are baked in a muffin tin so that they do not spread and lose their shape during cooking.