Preheat oven to 300 degrees F. Grease a 8x4-inch loaf pan with cooking spray. I also like to line the bottom of a loaf pan with parchment and allowing the ends to run up the sides. I find this easiest when I want to remove the loaf. Set aside.
In a small bowl, combine the chopped cranberries with the flour and set aside.
In a medium bowl, mix together the all-purpose flour, poppy seeds, salt and baking powder. Set aside.
In the bowl of stand-up mixer, add the sugar and orange zest. Rub the orange zest into the sugar, mixing it vigorously with your hands. This will bloom the orange zest flavors and oils.
Add the softened butter and vanilla extract to the bowl with the sugar. With the paddle attachment on the mixer, beat for about 5 minutes, until pale in color. Mix in one egg at a time, being sure each egg is incorporated before adding another.
Add the flour mixture into the butter mixture, alternating with the milk, beginning and ending with the flour. Pour in the cranberries and fold them in.
Pour the pound cake batter into the prepared 8x4-inch loaf pan and smooth out the top so it's nice and flat.
Transfer to the oven to bake for 60 to 65 minutes, until a skewer inserted into the center comes out clean. Allow the cake to cool for 5 minutes in the pan and then invert onto a cooling rack.