Preheat the oven to 325°F (160°C). Grease a 9x5 loaf pan with butter or non stick spray, and line it with parchment paper. Whisk flour, baking powder, salt and cinnamon together in a bowl and set aside.
Chop the dates into small pieces and add them to a heat proof bowl. Heat up the milk until hot (not boiling) and pour over the chopped dates. Stir, let it sit for 30 minutes.
In a large bowl, add room temperature butter and brown sugar. Beat on medium for a few minutes until well combined and lighter in color. Scrape the bowl half way through.
Add the eggs one at a time and mix well until incorporated.
Add vanilla extract and mix until combined.
Mix in the dry ingredients in 2 parts, alternating with milk and date mixture beating well after each addition. Be careful not to over-mix.
In a small bowl mix the chopped walnuts with 1 tsp of flour and fold it to the batter.
Transfer the batter to the prepared pan. I like to add a few more chopped walnuts on top.
Bake in the preheated oven for about 40-50 minutes or until a toothpick comes out clean. Check on it after 40 minutes and if the top is getting too brown but the center is not done yet, simply place a piece of aluminum foil on top of the pan and continue baking until it's done.
Let the cake cool in the pan for 10 minutes and then invert it onto a plate or wire rack.