You may know speculoos biscuits by the name of Biscoff.  Super easy to make and really very delicious.

 Ingredients 
50g room temperature butter
125g soft brown sugar or muscovado sugar
½ tsp vanilla extract
1 egg yolk
125g plain flour
½ tsp baking powder
1 tsp ground cinnamon 
½ tsp ground ginger
¼ tsp allspice
¼ tsp ground cloves
¼ ground cardamom

Method
Cream the butter, sugar and vanilla extract until a paste is formed.  Add the egg yolk and mix again until incorporated.  Put the flour and spices in a bowl together and mix so that the spices are mixed through the flour.  Add the flour to the butter mix and thoroughly mix into a smooth dough.  Refrigerate for half an hour.

When you are ready to bake, preheat the oven to 180c and lightly dust your board and rolling pin with flour.  Roll the dough out to 2-3mm and cut out with the cookie cutter of your choice.

Put the cut biscuits onto a lined baking tray with a little space around them - they don’t spread too much.  Cook for 15 minutes until golden.