Line a baking tray with parchment paper and preheat oven to 350°F
Place the pistachios in a ziptop bag and smash with a rolling pin until crushed into small pieces. They should be quite coarse.
Use a hand mixer or stand mixer with a paddle attachment, cream together the butter and sugar until light and fluffy. Mix in the vanilla extract until incorporated. Scrape down the sides of the bowl as needed.
Add the flour, crushed pistachios, cardamom, and salt. Mix on low speed until a cohesive dough forms.
Place the dough on a floured countertop. Flour the top of the dough and roll out with the rolling pin to about 1/8 of an inch thick. Cut out cookies about 2 - 3 inches in diameter. Place the cookies about 1/2 inch apart on the baking tray. Combine the dough scraps and roll out and cut more cookies until all the dough has been used. You should be able to get about 10 cookies.
Place the cookies in the fridge to chill for 10 minutes to prevent spreading in the oven.
Place the cookies on the middle rack and bake for 8 - 10 minutes until the edges just begin to brown.
Remove from the oven and let cool on the tray for 5 minutes.
While the cookies are cooling, prepare your ruby chocolate and pistachios. Crush the pistachios in a plastic bag, like in step 2. Set aside. Place pieces of chocolate in a small bowl and microwave for 20 second intervals until melted. After each 20 second interval, gently stir the chocolate.
Once the cookies are cooled, dip half of each cookie into the chocolate, or use a fork to drizzle chocolate over the cookies. Sprinkle with crushed pistachios to finish.