Preheat the oven to 350°F and grease a 9x5 inch loaf pan with cooking spray.
Beat the softened butter and 1 cup sugar in a stand mixer fitted with a paddle attachment until light and fluffy.
Add the eggs and vanilla extract to the butter mixture and beat well to combine.
In a food processor, pulse the cranberries with 1 tablespoon sugar until roughly chopped; alternatively, chop by hand or leave whole.
Gently mix the cranberries into the wet ingredients on low speed just until combined.
In a separate bowl, whisk together flour, baking powder, salt, and pistachio pudding mix to break up lumps.
Add half of the flour mixture to the wet ingredients on low speed, mixing just until incorporated.
Add the milk and mix to combine.
Add the remaining flour mixture and chopped pistachios, mixing just until combined.
Pour the batter into the prepared loaf pan and smooth the top.
Bake for 55 to 65 minutes, until a toothpick inserted in the center comes out clean.
Allow the bread to cool for a few minutes in the pan, then transfer to a wire rack to cool completely before slicing.