For the cookies:
2 3/4 cup AP flour
1 tsp baking powder
1/2 tsp salt
1 1/2 cups sugar
1 cup butter, room temperature
2 large eggs
2 tbsp sugar
2 tsp cinnamon

For the Biscoff cinnamon filling:
3 tbsp unsalted butter, room temperature
1/2 cup Biscoff spread or speculoos spread (or any nut butter)
1 cup confectioners sugar, sifted
1/2 tsp cinnamon
3 tbsp milk