Position a rack in the center of the oven and preheat the oven to 350°F. Then, grease and flour a 10-inch Bundt pan. Make sure to thoroughly cover all ridges so the cake comes out easily.
In a medium saucepan, combine the water, dates, and cinnamon stick. Bring the mixture to a boil over medium-high heat. Once boiling, remove the pan from the heat and allow to cool to room temperature. Remove the cinnamon stick from the mixture after it has cooled completely.
Next, sift together the flour, baking powder, baking soda, and salt into a medium bowl. Combine the dry ingredients by whisking and set aside.
In the bowl of a stand mixer (or a large bowl if you are using a hand mixer), beat the butter on medium-high speed until it is creamy. Use the paddle attachment if using a stand mixer. Once creamy, gradually add the brown sugar. Increase the speed to high and beat until the mixture is light and fluffy (about 3 minutes).
Beat in the eggs one at a time. Make sure to beat well after each addition (i.e., the eggs should be fully incorporated). Then, add the vanilla. Reduce the mixer speed to low and add the dry ingredients in 3 additions, alternating with two additions of the cooled date mixture (make sure the cinnamon stick has been removed). Do not over mix at this point. Only mix the flour until it is just incorporated.
Add the pecans and gently fold into the batter using a spatula. Scrape the edges and bottom of the bowl with a spatula to ensure that all ingredients have been incorporated and then pour batter into the prepared Bundt pan.