Preheat the oven to 350°F/180°C (160°C Fan oven), and line two half size sheet pans with parchment paper or Silpat silicone mat.
In a bowl, combine the dry ingredients (flour, baking soda, salt, and cinnamon), and set aside.
In a separate bowl, using a hand mixer (or a stand mixer), cream butter with sugars until smooth and creamy (2-3 minutes).
Add the egg, and vanilla extract and beat again for 1 minute.
Add the dry ingredients to the wet ingredients, and mix again on LOW speed until combined.
Fold in the chopped dates and pecans with a spatula.
Using a medium cookie scoop (1.5 tablespoon size), scoop out cookie balls onto the cookie sheet 1.5 inches apart.
Bake in a preheated oven for 10 minutes until the bottom of the cookie is lightly browned. Allow to cool completely on the cookie sheets.