Preheat and Prepare:

1. Preheat your oven to 350°F (175°C).
2. Grease and flour a 9×13-inch baking pan.

Make the Cake:

1. Finely grind the pistachios in a food processor until they are a coarse powder.
2. In a medium bowl, whisk together the ground pistachios, flour, baking powder, and salt.
3. In a large bowl, beat the softened butter and granulated sugar together until light and fluffy.
4. Add the eggs one at a time, beating well after each addition. Mix in the vanilla extract.
5. Gradually add the flour mixture to the butter mixture, alternating with the 1/2 cup of milk. Begin and end with the flour mixture.
6. Pour the batter into the prepared baking pan and spread it evenly.
7. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
8. Let the cake cool in the pan for about 10 minutes.

Prepare the Milk Mixture:

1. In a medium bowl, whisk together the coconut milk, sweetened condensed milk, and almond milk (or regular milk). Stir in the ground cardamom if using.
2. Poke holes all over the top of the cake using a fork or a skewer.
3. Slowly pour the milk mixture over the cake, making sure it soaks in. You might need to do this in batches, letting the cake absorb the milk before adding more.
4. Cover the cake and refrigerate for at least 4 hours, or overnight for best results.

Make the Whipped Cream Topping:

1. In a large bowl, whip the heavy cream with the powdered sugar and vanilla extract until stiff peaks form.
2. Spread the whipped cream evenly over the chilled cake.

Garnish and Serve:

1. Sprinkle the chopped pistachios over the top.
2. Cut into squares and serve.