Grind half the almonds; chop the rest roughly into small pieces.

Preheat oven to 350 degrees F (175 degrees C). Line 2 baking sheets with parchment paper.

Melt butter in a saucepan over medium heat. Stir in brown sugar; cook and mix until dissolved, 2 to 3 minutes. Remove from heat. Let caramel mixture cool to room temperature.

Mix 2 cups plus 1 tablespoon flour, cinnamon, ginger, baking powder, and nutmeg together in a bowl until well incorporated.

Stir ground almonds, eggs, vanilla extract, and salt into the cooled caramel mixture. Add the flour mixture gradually; mix until well combined. Stir in the chopped almonds. Roll dough into 36 balls; flatten slightly and place them, evenly spaced, onto the prepared baking sheets. Press pistachios into the dough.

Bake in the preheated oven until golden brown but still soft to the touch, 10 to 12 minutes. Cool in the pan for 10 to 15 minutes.