Line two cookie sheets with parchment paper and set them aside.
Combine the flour, baking powder and salt in a large mixing bowl. Mix until combined well, then set aside.
Next, combine the softened butter and brown sugar in a separate large mixing bowl. Cream the ingredients together by beating them with a mixer until the mixture is fluffy and light brown in color. This should take approximately 4 to 5 minutes.
Then, add the molasses, egg and vanilla extract to the bowl with the sugar mixture you just beat. Mix the ingredients again until well combined.
Next, add the dry ingredients to the wet ingredients and mix until they are well combined.
Carefully add the chocolate chips and pistachios to the bowl and mix by hand with a spatula or wooden spoon just enough to combine the ingredients well. You can add more pistachios or chocolate chips if you like.
Grab your cookie sheets you set aside earlier. Spoon the cookie dough onto the sheets, spacing evenly. Space them about 2 inches apart. You can easily adjust the size of the cookies. Make tiny ones or giant ones. Just adjust the cooking time a bit to account for the size of the cookies.
Transfer the cookie sheets to the preheated oven and bake for about 8 to 10 minutes for small-ish cookies, or 10 to 12 minutes for large-ish cookies. I typically cook one pan at a time because I like baking them on the middle rack and hate rotating cookies mid-bake. But if you are in a rush go ahead and bake both at the same time.
Carefully remove the cookies from the oven and allow them to cool slightly on the pan, then transfer them to a cooling rack to allow them to cool completely.
Serve or store for later.
Notes
If you don't want your cookies to spread as much you can always chill the dough for a minimum of 30 minutes, or up to 24 hours. I did not chill mine for these particular cookies.