Mix flour, sugar, baking powder and pinch of salt.
Add spices. You can add a teaspoon of cinnamon, and 1/4 teaspoon of nutmeg, ginger, aniseeds and clove. Adjust to taste. Some people add white ground pepper, others add red pepper too. Anything goes but don't overdo it.
Add the butter, first use a fork to flatten and soften it, then use your hands to mix it in the flour and sugar. The result should be more like greasy sugar than like dough.
Make a hole in the middle and add the yolk. Collapse the hole, and continue mixing with your hands.
Make another hole in the middle and add the milk. Collapse again, and continue mixing. The dough is good when it sticks on your hands, but not on the surface.
Roll the dough into a piece of baking paper, tin foil or a kitchen towel, and leave in a cold place (eg. a fridge) overnight.
preheat oven to 175° C
Take the roll of dough and cut into round cookies of about 3-4 mm thick. Alternatively, roll out the dough and use cookie forms. Traditionally, speculaas dough is rolled over wooden speculaas baking forms and turned over to produce an image and shape.
Allow to bake at 175° for about 25 minutes. The cookies should rise gently. Check if they're ready by tapping a spoon onto a cookie. If there is dough sticking on the cookie, it's not ready yet. At this stage the cookies are still soft and should slightly budge under the spoon. If they're getting black around the edges, they're overcooked.
Allow to cool for about 25 minutes. This gives the cookies time to harden and become real speculaas cookies.
Best kept (for weeks if necessary) in a firmly closed tin box.