Warm up the milk in a microwave for about 30 seconds or until piping hot. Add the tea to the milk and cover. Set aside and let steep while you prepare the other ingredients.
Preheat the oven to 350 F. Prepare a baking sheet by lining it with parchment paper.
In a large bowl, whisk together the flour, baking powder, nutmeg, ginger, and cardamom. Set aside.
In another large bowl or a stand mixer bowl, add the sugar, butter, and salt and beat well. Strain the milk, if using tea leaves. Add the steeped tea and mix. Add the eggs one at a time and mix well.
Add the flour mixture and beat just until all the ingredients are combined.
Stir in the pistachios by hand so that the nuts don’t break up.
Form the dough into two 3-in by 8-in logs and place 3-in apart on the prepared baking sheet. Bake until golden, about 40 minutes. Cool for 30 minutes.
Using a serrated knife, carefully cut the logs into ½-in to ¾-in thick slices. Arrange the slices on the baking sheet, cut side down, and bake for 15 minutes. Transfer the cookies onto a rack and let them cool completely. Store in an air-tight container for up to 5 days.