Preheat the oven to 300 degrees. Lightly grease an 8 inch square pan, line with baking parchment, then lightly grease the paper.
In a small bowl, whisk together the flour, cinnamon, baking powder and salt.
In a larger bowl, cream the butter until light. add the sugars, and cream until they are well mixed.
Stir in the flour just until combined, then press the mixture into the prepared pan.
Stir together the topping ingredients and sprinkle them over the crust.
Bake the cookies for about 30 to 35 minutes until nicely browned. Cut them in the pan while they are still warm. Allow them to finish cooling on a wire rack.